(Download) CBSE Class-10 2016-17 Sample Paper And Marking Scheme (Hindi-B)

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(Download) CBSE Class-12 2016-17 Sample Paper (Entrepreneurship)

Time allowed: 3 hours

Maximum Marks: 70

1. Name the two things that are taken care in a reorder point? 5 (U) 1

Ans. Lead time and Demand during lead time.

2. Deepak Ltd., has been manufacturing cycles since 2010. Their market share in this field is 35%. They decided to introduce new cycles with advanced gear systems in 2015. For the same they estimated their financial requirements to be 20 crore.

They decided to raise the same through a limited number of sophisticated investors. Identify this kind of issue?

Ans. Private placement

3. Rishabh lives in Vijay Nagar, a residential colony near Delhi University (DU). Being close to DU this area is a hub for students who come from outside Delhi to study here as they find good accommodation with Tiffin service readily available. Rishabh has a vacant residential building there. He found it to be an attractive economic idea to start a Paying Guest House. He knows that he has a good market because of the location of his building. State the other requirement he has to ensure before opting for this opportunity.

Ans. The rate of return on the investment has to be attractive to be accepted by him.

4. What is meant by ‘private sector enterprise’? 2/ (R) 1

Ans. Private sector enterprises are those which are owned, controlled, and managed by private individuals, with the main objective of earning profit.

5. State the role of a sales person in personal selling. 3/ (R) 1

Ans. Companies appoint salesperson to contact prospective buyers and create awareness about the company’s product.

6. What is meant by seed capital financing? What the entrepreneur has to do to convince the investor to get money?

Ans. It refers to the capital required by an entrepreneur for conducting research at pre commercialization stage. The entrepreneur has to convince that his idea was worthwhile to the investor.

7. Ragini, a career oriented mother, hardly got time to cook for the family. She decided to hire a cook but was not able to find one who could cook according to the taste of the family. Her sister Abha sensed that this problem is not only faced by her sister but also by many working women. She launched a website namely ‘Dial for food’ where housewives who had culinary ability and were interested to cook could drop in their contact details and households where specific cuisine was required could leave in their requirements so that through the website home cooked food could be delivered. The website mainly helped in identifying the requirement and fulfilled it through providing delivery service. Identify any two uses of problem identification to Abha.

Ans. 1. Bring out new products in the market

2. Increase employment generation

3. Understand the problems and needs of the market. (Any two)

8. Explain the first two elements in the innovation process? 1/U 2

Ans. 1. Analytical planning: carefully identifying the product or service features, design as well as the resources that will be needed.

2. Resource organization: obtaining the required resources, materials, technology, human or capital resources.

9. Sanjiv was developing a business plan for his organization. While working on the financial plan he realised that his financial requirements will be for fixed assets and their installations, preliminary expenses, working capital, expenses on research and development and investment in short-term assets viz. raw material, level of cash, etc. To decide on the sources of funds for the venture, he tried to ensure the selection of the best overall mix of financing for the enterprise.

a. Identify the elements of financial plan discussed here.
b. Why is it important for an entrepreneur to ensure the selection of the best overall mix of financing for the enterprise?

Ans. a. a) Proforma investment decisions
b) Proforma financing decisions
b. The entrepreneur's job is to ensure the selection of the best overall mix of financing for the enterprise so that:
a) the cost of capital and the financial risk stands minimized,
b) return on investment and profitability stands maximized.

10. Rohan a budding musician created a lot of musical notes for his upcoming video. He was extremely thrilled to listen to his compositions. He presented his compositions to his friend Victor. The release of musical video of Rohan was getting delayed for a few months due to shortage of cash. Meanwhile Victor used most of the musical compositions of Rohan in his video.

Rohan was extremely upset to know that his friend had cheated him and used all his work. What could have Rohan done to save his work?

Identify and explain it.

Ans. Rohan should have copyrighted his work. It gives the creator of original work exclusive rights to it, usually for a limited time.

11. Bhushan and Vinay were pursuing Electrical Engineering from a prestigious engineering college. During their third year they developed a solar LED bulb which can be used indoors. The bulb had a small panel which had to be charged at a stretch for 10 hours in the sun and it would last for 200 hours of usage. The idea was risky as there was a possibility that the market might not accept such a product, but if they do so, then, there would be a revolution in the power industry as it would lead to saving of power in every household.

The prototype was made but to manufacture and distribute the same, they required around 5 crores. Both Bhushan and Vinay approached some affluent individuals who were ready to invest in their business in exchange for a convertible debt. Identify the type of investors and state any two features of the same.

Ans. Angel Investor

Features (Any two)
1. Most angel investors are current or retired executives, business owners or high net worth individuals who have the knowledge, expertise, and funds that help start-ups match up to industry standards.
2. As angel investors bear extremely high risk and are usually subject to dilution from future investment rounds. They expect a very high return on investment.
3. Apart from investing funds, most angels provide proactive advice,guidance, industry connections and mentoring start-ups in its early days.
4. Their objective is to create great companies by providing value creation, and simultaneously helping investors realize a high returnon investments.
5. They have a sharp inclination to keep abreast of current developments in a particular business arena, mentoring another generation of entrepreneurs by making use of their experience.

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(Book) National Geographic Little Kids First Big Book of Why

Book Details:

Reading level: 3 - 7 years

Hardcover: 128 pages

Publisher: National Geographic Children's Books (10 May 2011)

Language: English

ISBN-10: 1426307934

ISBN-13: 978-1426307935

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(Download) CBSE Class-12 2016-17 Sample Paper And Marking Scheme (Fashion Studies)

Time: 3hours M.M.70

SECTION-A

Q1. Define the term ‘roll line’.

Q2.How much should be the seam allowance on side seam and straight hemline of a garment?

Q3. Why ‘Kani’ were regarded as luxuries in Europe?

Q4.From where the word ‘ready to wear’ is derived?

Q5. Name any two fabrics used frequently for men’s casual wear garments.

Q6. Suggest an underlining to achieve a luxurious finish.

Q7.Mention the method to achieve Kimono sleeve.

Section –B

Q8.State the origin of the word ‘Khaki’. Why Khaki coloured uniforms have become synonymous with uniform and law enforcement services in India? 2

Q9. What were the prevalent radical options in draping the sari during 1970? 2

Q10. The famous designer Schiaparelli’s designs had an artistic approach and influenced by

Surrealism movement.’ Support the statement by giving relevant example. 2

Q11. A popular finish bias piping is used for blouses and other Indian garments. How is it different from bias facing? 2

OR

Differentiate between test fitting and garment fitting.

Q12. Sanya is dressed up in a skirt for a birthday party. How can she check the element of ‘balance’ in the skirt? 2

Q13. List two types each of skirts and pants worn by women. 2

Q14. a) How is French placket constructed?
b) Where is it normally used? 2

Q15. Categorize two determining factors that affect the type of underlining. 2

SECTION-C

Q16. (a) ‘The costumes worn by screen characters in successful movies and television serials, are influential in creating market demand for similar styles at affordable price points. Justify.
b) The movies Bandit Queen and The Dirty Picture have won National award for Best costume. Name the costume designers for both the movies.

c) Name the event which exclusively showcases wedding trousseau wear.

Q17. Plan steps to prepare ‘U-neckline’. Support the answer with neat diagram. 2+1=3

OR

Explain steps to develop Mandarin Collar, with the help of neat diagram.

Q18. a) Why pattern designers started draping their patterns on a dress form?
b) Give reason for draping not suitable method for ready to wear market.
c) Define the term ‘pattern’.

Q19. Discuss the use of following equipments:
a. Large scissors
b. Small scissors
c. Seam ripper

Q20. Rahul is a toddler. What kind of colours, fabrics and patterns should be preferred by his mother to purchase clothes for him? 3

Q21. Elaborate the following terms:
a. Fashion show
b. Petite
c. Baggy trouser

Q22. Explain three different types of grainlines.

Q23. Suggest the patterns to be avoided with diagonal print. Also suggest patterns most suitable with even plaids. 2+1=3

Q24. What are blended fabrics? Why do consumers feel confused in identifying the synthetics?
 

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(Download) CBSE Class-10 2016-17 Sample Paper And Marking Scheme (Home Science)

Time: 3 Hrs Maximum

Marks: 80

General Instructions:

1. All questions are compulsory.
2. There are in all 27 questions.
3. Question no.1-5 are of 1 mark, to be answered in one or two lines.
4. Question no.6-12 are of 2 marks, to be answered in 10-20 words.
5. Question no.13-15 are of 3 marks , to be answered in 20-30 words.
6. Question no.16-23 are of 4 marks, to be answered in 40 words.
7. Question no.24-27 are of 5 marks, to be answered in 50-60 words.
8. Support your answer with suitable examples and figures wherever required.

1. Which is an example of physical fatigue:

(a) fatigue due to cycling
(b) fatigue due to a stressful day
(c) fatigue due to waiting for a bus
(d) fatigue due to spending time in a hospital

2. To remove blood stains from white cotton fabric

(a) Use hot water and salt
(b) Use hot iron
(c) Use cold water and salt
(d) Use talcum powder

3. Ironing should not be done directly on the _________.

(a) Collars
(b) Cuffs
(c) sleeves
(d) buttons

4. ___________ an example of direct income

(a) living in own house
(b) salary of individual
(c) hired maid
(d) uniform from office

5. Stress and storm is a typical phase of:

a) early childhood
b) adolescence
c) adulthood
d) old age

6. Neeta got a stain on her white shirt. She does not know the nature of stain. Tell her two ways to identify the nature the stain along with the examples.

7. Write any two advantages of using food groups in planning a balanced diet.

8. ‘Money is a pivotal resource”. Write any four ways of saving this resource while going for shopping.

9. State with example how cultural factors influence meal planning. 2

10. Convince your friend the importance of soaking cloths before scrubbing.

11. Give four tips to your friend to save her energy while rearranging her wardrobe.

12. What is AGMARK? Name any two products that are given this quality mark.

13. Give one influence of each availability of food items, age and cost of food items on meal planning.

14. Your father has come from his office little early and looking very stressed. Suggest him six ways to reduce the psychological fatigue.

15. Your uncle is not able to adjust with his old father. Explain him the changes which occur during old age and how can he take care of his father’s special needs?

16. Define meal planning. State any six advantages of it. 4

17. Sunita has to wash her woolen and silk clothes. Tell her any four differences in the process of washing the clothes.

18. Educate a group of Anganwadi workers about the important features of RDA.

19. You have wheat, rice, rajma, potato, peanuts, refined oil, spinach, paneer, eggs, oranges, bottle guard, apples and butter in your kitchen. Segregate them according to the food groups as given by ICMR and explain their nutrition value.

20. Skill of a Home Science student can help her family to increase the real income. Support the statement with the help of any eight examples.

21. You have purchased unpacked milk from a new milk vendor. How will you ensure that you are not being cheated?

22. When would you describe an advertisement of a product as ‘misleading’? Explain with suitable examples.

23. What are the different stages of adulthood? Write two characteristics of each stage.

24. Your mother has started a small scale business of food preservation. Keeping in mind the requisites of a good label, draw a label for apple jam.

25. You got an unknown stain on your school uniform. What procedure will you follow to remove it?

26. Nitin is a labourer and earning Rs. 10,000 per month. Is this, one of the important factor that can influence the expenditure of his family? If yes, explain with examples four more factors that can influence the same.

27. Your term II examination is going to start after a month. Plan your time accordingly, keeping in mind the various steps involved in it.

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NCERT  Hindi Question Paper (Class-10)

Chapter 1 Soor Das ke Pad

1- गोपियों द्वारा उद्धव को भाग्यवान कहने में क्या व्यंग्य निहित है?

2- उद्धव के व्यवहार की तुलना किस-किस से की गई है?

3- गोपियों ने किन-किन उदाहरणों के माध्यम से उद्धव को उलाहने दिए हैं?

4- उद्धव द्वारा दिए गए योग के संदेश ने गोपियों की विरहाग्नि में घी का काम कैसे किया?

5- ‘मरजादा न लही’ के माध्यम से कौन-सी मर्यादा न रहने की बात की जा रही है?

6- कृष्ण के प्रति अपने अनन्य प्रेम को गोपियों ने किस प्रकार अभिव्यक्त किया है?

7- गोपियों ने उद्धव से योग की शिक्षा कैसे लोगों को देने की बात कही है?

8- प्रस्तुत पदों के आधार पर गोपियों का योग-साधना के प्रति दृष्टिकोण स्पष्ट करें।

9- गोपियों के अनुसार राजा का धर्म क्या होना चाहिए?

10- गोपियों को कृष्ण में ऐसे कौन-से परिवर्तन दिखाई दिए जिनके कारण वे अपना मन वापस पा लेने की बात कहती हैं?

11- गोपियों ने अपने वाव्फ़चातुर्य के आधार पर ज्ञानी उद्धव को परास्त कर दिया, उनके वाव्फ़चातुर्य की विशेषताएँ लिखिए?

12- संकलित पदों को ध्यान में रखते हुए सूर के भ्रमरगीत की मुख्य विशेषताएँ बताइए? रचना और अभिव्यक्ति

13- गोपियों ने उद्धव के सामने तरह-तरह के तर्क दिए हैं, आप अपनी कल्पना से और तर्क दीजिए।

14- उद्धव ज्ञानी थे, नीति की बातें जानते थे_ गोपियों के पास ऐसी कौन-सी शक्ति थी जो उनके वाव्फ़चातुर्य में मुखरित हो उठी?

15- गोपियों ने यह क्यों कहा कि हरि अब राजनीति पढ़ आए हैं? क्या आपको गोपियों के इस कथन का विस्तार समकालीन राजनीति में नजर आता है,
स्पष्ट कीजिए। पाठेतर सक्रियता प्रस्तुत पदों की सबसे बड़ी विशेषता है गोपियों की ‘वाग्विदग्धता’। आपने ऐसे और चरित्रें के बारे में पढ़ा या सुना होगा जिन्होंने अपने वाव्फ़चातुर्य के आधार पर अपनी एक विशिष्ट पहचान बनाई_ जैसेμबीरबल, तेनालीराम, गोपालभाँड, मुल्ला नसीरुद्दीन आदि। अपने किसी मनपसंद चरित्र के कुछ किस्से संकलित कर एक अलबम तैयार करें। सूर रचित अपने प्रिय पदों को लय व ताल के साथ गाएँ।

रचना और अभिव्यक्ति

13- गोपियों ने उद्धव के सामने तरह-तरह के तर्क दिए हैं, आप अपनी कल्पना से और तर्क दीजिए।

14- उद्धव ज्ञानी थे, नीति की बातें जानते थे_ गोपियों के पास ऐसी कौन-सी शक्ति थी जो उनके वाव्फ़चातुर्य में मुखरित हो उठी?

15- गोपियों ने यह क्यों कहा कि हरि अब राजनीति पढ़ आए हैं? क्या आपको गोपियों के इस कथन का विस्तार समकालीन राजनीति में नजर आता है, स्पष्ट कीजिए।

Chapter 2 Ram Lakshman Parshuram Samvad

राम-लक्ष्मण-परशुराम संवाद

प्रश्न-अभ्यास

1- परशुराम के क्रोध करने पर लक्ष्मण ने धनुष के टूट जाने के लिए कौन-कौन से तर्क दिए?

2- परशुराम के क्रोध करने पर राम और लक्ष्मण की जो प्रतिक्रियाएँ हुईं उनके आधार पर दोनों के स्वभाव की विशेषताएँ अपने शब्दों में लिखिए।

3- लक्ष्मण और परशुराम के संवाद का जो अंश आपको सबसे अच्छा लगा उसे अपने शब्दों में संवाद शैली में लिखिए।

4- परशुराम ने अपने विषय में सभा में क्या-क्या कहा, निम्न पद्यांश के आधार पर लिखिएμ
बाल ब्रह्मचारी अति कोही।
भुजबल भूमि भूप बिनु कीन्ही।
सहसबाहुभुज छेदनिहारा।
बिस्वबिदित क्षत्रियकुल द्रोही।।
बिपुल बार महिदेवन्ह दीन्ही।।
परसु बिलोकु महीपकुमारा।।
मातु पितहि जनि सोचबस करसि महीसकिसोर।
गर्भन्ह के अर्भक दलन परसु मोर अति घोर।।

5- लक्ष्मण ने वीर योद्धा की क्या-क्या विशेषताएँ बताईं?

6- साहस और शक्ति के साथ विनम्रता हो तो बेहतर है। इस कथन पर अपने विचार लिखिए।

7- भाव स्पष्ट कीजिएμ
(क) बिहसि लखनु बोले मृदु बानी। अहो मुनीसु महाभट मानी।।
पुनि पुनि मोहि देखाव कुठारू। चहत उड़ावन फूंँकि पहारू।।

(ख) इहाँ कुम्हड़बतिया कोउ नाहीं। जे तरजनी देखि मरि जाहीं।।
देखि कुठारु सरासन बाना। मैं कछु कहा सहित अभिमाना।।

(ग) गाधिसूनु कह हृदय हसि मुनिहि हरियरे सूझ।
अयमय खाँड़ न ऊखमय अजहुँ न बूझ अबूझ।।

8- पाठ के आधार पर तुलसी के भाषा सौंदर्य पर दस पंक्तियाँ लिखिए।

9- इस पूरे प्रसंग में व्यंग्य का अनूठा सौंदर्य है। उदाहरण के साथ स्पष्ट कीजिए।

10- निम्नलिखित पंक्तियों में प्रयुक्त अलंकार पहचान कर लिखिएμ
(क) बालकु बोलि बधौं नहि तोही।

(ख) कोटि कुलिस सम बचनु तुम्हारा।

(ग) तुम्ह तौ कालु हाँक जनु लावा।
बार बार मोहि लागि बोलावा।।

(घ) लखन उतर आहुति सरिस भृगुबरकोपु कृसानु।
बढ़त देखि जल सम बचन बोले रघुकुलभानु।।

रचना और अभिव्यक्ति

11- फ्सामाजिक जीवन में क्रोध की जरूरत बराबर पड़ती है। यदि क्रोध न हो तो मनुष्य दूसरे के द्वारा पहुँचाए जाने वाले बहुत से कष्टों की चिर-निवृत्ति का उपाय ही न कर सके।य्
आचार्य रामचंद्र शुक्ल जी का यह कथन इस बात की पुष्टि करता है कि क्रोध हमेशा नकारात्मक भाव तुलसीदास

Chapter 3 Dev ke Saviaya aur Kavitt

प्रश्न-अभ्यास

1- कवि ने ‘श्रीब्रजदूलह’ किसके लिए प्रयु क्त किया है और उन्हें संसार रूपी मंदिर का दीपक क्यों कहा है?

2- पहले सवैये में से उन पंक्तियों को छाँटकर लिखिए जिनमें अनुप्रास और रूपक अलंकार का प्रयोग हुआ है?

3- निम्नलिखित पंक्तियों का काव्य-सौंदर्य स्पष्ट कीजिएμ
पाँयनि नूपुर मंजु बजैं, कटि किकिनि कै धुनि की मधुराई।
साँवरे अंग लसै पट पीत, हिये हुलसै बनमाल सुहाई।

4- दूसरे कवित्त के आधार पर स्पष्ट करें कि ऋतुराज वसंत के बाल-रूप का वर्णन परंपरागत वसंत वर्णन से किस प्रकार भिन्न है।

5- ‘प्रातहि जगावत गुलाब चटकारी दै’μ इस पंक्ति का भाव स्पष्ट कीजिए।

6- चाँदनी रात की सुंदरता को कवि ने किन-किन रूपों में देखा है?

7- ‘प्यारी राधिका को प्रतिबिब सो लगत चंद’μइस पंक्ति का भाव स्पष्ट करते हुए बताएँ कि इसमें कौन-सा अलंकार है?

8- तीसरे कवित्त के आधार पर बताइए कि कवि ने चाँदनी रात की उज्ज्वलता का वर्णन करने के लिए किन-किन उपमानों का प्रयोग किया है?

9- पठित कविताओं के आधार पर कवि देव की काव्यगत विशेषताएँ बताइए।

रचना और अभिव्यक्ति

10- आप अपने घर की छत से पूर्णिमा की रात देखिए तथा उसके सौंदर्य को अपनी कलम से शब्दबद्ध कीजिए।

पाठेतर सक्रियता

भारतीय ऋतु चक्र में छह ऋतुएँ मानी गई हैं, वे कौन-कौन सी हैं?
‘ग्लोबल वार्मिंग’ के कारण ऋतुओं में क्या परिवर्तन आ रहे हैं? इस समस्या से निपटने के लिए
आपकी क्या भूमिका हो सकती है?

Chapter 4 Jai Sankar Prasad Atmkadya

जयशंकर प्रसाद आत्मकथ्य

प्रश्न-अभ्यास

1- कवि आत्मकथा लिखने से क्यों बचना चाहता है?

2- आत्मकथा सुनाने के संदर्भ में ‘अभी समय भी नहीं’ कवि ऐसा क्यों कहता है?

3- स्मृति को ‘पाथेय’ बनाने से कवि का क्या आशय है?

4- भाव स्पष्ट कीजिएμ
(क) मिला कहाँ वह सुख जिसका मैं स्वप्न देखकर जाग गया।
आलिगन में आते-आते मुसक्या कर जो भाग गया।

(ख) जिसके अरुण कपोलों की मतवाली सुंदर छाया में।
अनुरागिनी उषा लेती थी निज सुहाग मधुमाया में।

5- ‘उज्ज्वल गाथा कैसे गाऊँ, मधुर चाँदनी रातों की’μकथन के माध्यम से कवि क्या कहना चाहता है?

6- ‘आत्मकथ्य’ कविता की काव्यभाषा की विशेषताएँ उदाहरण सहित लिखिए।

7- कवि ने जो सुख का स्वप्न देखा था उसे कविता में किस रूप में अभिव्यक्त किया है?

रचना और अभिव्यक्ति

8- इस कविता के माध्यम से प्रसाद जी के व्यक्तित्व की जो झलक मिलती है, उसे अपने शब्दों में लिखिए।

9- आप किन व्यक्तियों की आत्मकथा पढ़ना चाहेंगे और क्यों?

10- कोई भी अपनी आत्मकथा लिख सकता है। उसके लिए विशिष्ट या बड़ा होना जरूरी नहीं। हरियाणा राज्य के गुड़गाँव में घरेलू सहायिका के रूप में काम करने वाली बेबी हालदार की आत्मकथा फ्आलो अांधारिय् बहुतों के द्वारा सराही गई। आत्मकथात्मक शैली में अपने बारे में कुछ लिखिए।

पाठेतर सक्रियता

किसी भी चर्चित व्यक्ति का अपनी निजता को सार्वजनिक करना या दूसरों का उनसे ऐसी अपेक्षा करना सही हैμइस विषय के पक्ष-विपक्ष में कक्षा में चर्चा कीजिए।
बिना ईमानदारी और साहस के आत्मकथा नहीं लिखी जा सकती। गांधी जी की आत्मकथा ‘सत्य के प्रयोग’ पढ़कर पता लगाइए कि उसकी क्या-क्या विशेषताएँ हैं?

Chapter 5 Suryakant Tripathi Nirala Utsah

उत्साह

प्रश्न-अभ्यास

1- कवि बादल से फुहार, रिमझिम या बरसने के स्थान पर ‘गरजने’ के लिए कहता है, क्यों?

2- कविता का शीर्षक उत्साह क्यों रखा गया है?

3- कविता में बादल किन-किन अर्थों की ओर संकेत करता है?

4- शब्दों का ऐसा प्रयोग जिससे कविता के किसी खास भाव या दृश्य में ध्वन्यात्मक प्रभाव पैदा हो, नाद-सौंदर्य कहलाता है। उत्साह कविता में ऐसे कौन-से शब्द हैं जिनमें नाद-सौंदर्य मौजूद है, छाँटकर लिखें।

रचना और अभिव्यक्ति

5- जैसे बादल उमड़-घुमड़कर बारिश करते हैं वैसे ही कवि के अंतर्मन में भी भावों के बादल उमड़-घुमड़कर कविता के रूप में अभिव्यक्त होते हैं। ऐसे ही किसी प्राकृतिक सौंदर्य को देखकर अपने उमड़ते भावों को कविता में उतारिए।

पाठेतर सक्रियता

बादलों पर अनेक कविताएँ हैं। कुछ कविताओं का संकलन करें और उनका चित्रंकन भी कीजिए। अट नहीं रही है

1- छायावाद की एक खास विशेषता है अंतर्मन के भावों का बाहर की दुनिया से सामंजस्य बिठाना। कविता की किन पंक्तियों को पढ़कर यह धारणा पुष्ट होती है? लिखिए।

2- कवि की आँख फागुन की सुंदरता से क्यों नहीं हट रही है?

3- प्रस्तुत कविता में कवि ने प्रकृति की व्यापकता का वर्णन किन रूपों में किया है?

4- फागुन में ऐसा क्या होता है जो बाकी ऋतुओं से भिन्न होता है?

5- इन कविताओं के आधार पर निराला के काव्य-शिल्प की विशेषताएँ लिखिए।

रचना और अभिव्यक्ति

6- होली के आसपास प्रकृति में जो परिवर्तन दिखाई देते हैं, उन्हें लिखिए।

Chapter 6 Yah Dandurit Muskan

यह दंतुरित मुसकान

यह दंतुरित मुसकान

1- बच्चे की दंतुरित मुसकान का कवि के मन पर क्या प्रभाव पड़ता है?

2- बच्चे की मुसकान और एक बड़े व्यक्ति की मुसकान में क्या अंतर है?

3- कवि ने बच्चे की मुसकान के सौंदर्य को किन-किन बिबों के माध्यम से व्यक्त किया है?

4- भाव स्पष्ट कीजिएμ
(क) छोड़कर तालाब मेरी झाेंपड़ी में खिल रहे जलजात।
(ख) छू गया तुमसे कि झरने लग पड़े शेफालिका के फूल बाँस था कि बबूल?

रचना और अभिव्यक्ति

5- मुसकान और क्रोध भिन्न-भिन्न भाव हैं। इनकी उपस्थिति से बने वातावरण की भिन्नता का चित्रण कीजिए।

6- दंतुरित मुसकान से बच्चे की उम्र का अनुमान लगाइए और तर्क सहित उत्तर दीजिए।

7- बच्चे से कवि की मुलाकात का जो शब्द-चित्र उपस्थित हुआ है उसे अपने शब्दों में लिखिए।

पाठेतर सक्रियता

आप जब भी किसी बच्चे से पहली बार मिलें तो उसके हाव-भाव, व्यवहार आदि को सूक्ष्मता से देखिए और उस अनुभव को कविता या अनुच्छेद के रूप में लिखिए।

1- कवि के अनुसार फसल क्या है?
2- कविता में फसल उपजाने के लिए आवश्यक तत्वों की बात कही गई है। वे आवश्यक तत्व कौन-कौन से हैं?
3- फसल को ‘हाथों के स्पर्श की गरिमा’ और ‘महिमा’ कहकर कवि क्या व्यक्त करना चाहता है?

4- भाव स्पष्ट कीजिएμ
(क) रूपांतर है सूरज की किरणों का सिमटा हुआ संकोच है हवा की थिरकन का!
रचना और अभिव्यक्ति

5- कवि ने फसल को हजार-हजार खेतों की मि‘ी का गुण-धर्म कहा हैμ
(क) मि‘ी के गुण-धर्म को आप किस तरह परिभाषित करेंगे?
(ख) वर्तमान जीवन शैली मि‘ी के गुण-धर्म को किस-किस तरह प्रभावित करती है?
(ग) मि‘ी द्वारा अपना गुण-धर्म छोड़ने की स्थिति में क्या किसी भी प्रकार के जीवन की कल्पना की जा सकती है?
(घ) मि‘ी के गुण-धर्म को पोषित करने में हमारी क्या भूमिका हो सकती है?

पाठेतर सक्रियता

इलेक्ट्रॉनिक एवं प्रिट मीडिया द्वारा आपने किसानों की स्थिति के बारे में बहुत कुछ सुना, देखा और पढ़ा होगा। एक सुदृढ़ कृषि-व्यवस्था के लिए आप अपने सुझाव देते हुए अखबार के संपादक को पत्र लिखिए। फसलों के उत्पादन में महिलाओं के योगदान को हमारी अर्थव्यवस्था में महत्त्व क्यों नहीं दिया जाता है? इस बारे में कक्षा में चर्चा कीजिए।

Chapter 7 Chaya Mat Chhoona

छाया मत छूना

प्रश्न-अभ्यास

1- कवि ने कठिन यथार्थ के पूजन की बात क्यों कही है?

2- भाव स्पष्ट कीजिएμ
प्रभुता का शरण-बिब केवल मृगतृष्णा है,
हर चंद्रिका में छिपी एक रात कृष्णा है।

3- ‘छाया’ शब्द यहाँ किस संदर्भ में प्रयुक्त हुआ है? कवि ने उसे छूने के लिए मना क्यों किया है?

4- कविता में विशेषण के प्रयोग से शब्दों के अर्थ में विशेष प्रभाव पड़ता है, जैसे कठिन यथार्थ। कविता में आए ऐसे अन्य उदाहरण छाँटकर लिखिए और यह भी लिखिए कि इससे शब्दों के अर्थ में क्या विशिष्टता पैदा हुई?

5- ‘मृगतृष्णा’ किसे कहते हैं, कविता में इसका प्रयोग किस अर्थ में हुआ है?

6- ‘बीती ताहि बिसार दे आगे की सुधि ले’ यह भाव कविता की किस पंक्ति में झलकता है?

7- कविता में व्यक्त दुख के कारणों को स्पष्ट कीजिए।

रचना और अभिव्यक्ति

8- ‘जीवन में हैं सुरंग सुधियाँ सुहावनी’, से कवि का अभिप्राय जीवन की मधुर स्मृतियों से है। आपने अपने जीवन की कौन-कौन सी स्मृतियाँ संजो रखी हैं?

9- ‘क्या हुआ जो खिला फूल रस-बसंत जाने पर?’ कवि का मानना है कि समय बीत जाने पर भी उपलब्धि मनुष्य को आनंद देती है। क्या आप ऐसा मानते हैं? तर्क सहित लिखिए।

प्रश्न-अभ्यास

1- कवि ने कठिन यथार्थ के पूजन की बात क्यों कही है?

2- भाव स्पष्ट कीजिएμ
प्रभुता का शरण-बिब केवल मृगतृष्णा है,
हर चंद्रिका में छिपी एक रात कृष्णा है।

3- ‘छाया’ शब्द यहाँ किस संदर्भ में प्रयुक्त हुआ है? कवि ने उसे छूने के लिए मना क्यों किया है?

4- कविता में विशेषण के प्रयोग से शब्दों के अर्थ में विशेष प्रभाव पड़ता है, जैसे कठिन यथार्थ। कविता में आए ऐसे अन्य उदाहरण छाँटकर लिखिए और यह भी लिखिए कि इससे शब्दों के अर्थ में क्या विशिष्टता पैदा हुई?

5- ‘मृगतृष्णा’ किसे कहते हैं, कविता में इसका प्रयोग किस अर्थ में हुआ है?

6- ‘बीती ताहि बिसार दे आगे की सुधि ले’ यह भाव कविता की किस पंक्ति में झलकता है?

7- कविता में व्यक्त दुख के कारणों को स्पष्ट कीजिए।

रचना और अभिव्यक्ति

8- ‘जीवन में हैं सुरंग सुधियाँ सुहावनी’, से कवि का अभिप्राय जीवन की मधुर स्मृतियों से है। आपने अपने जीवन की कौन-कौन सी स्मृतियाँ संजो रखी हैं?

9- ‘क्या हुआ जो खिला फूल रस-बसंत जाने पर?’ कवि का मानना है कि समय बीत जाने पर भी उपलब्धि मनुष्य को आनंद देती है। क्या आप ऐसा मानते हैं? तर्क सहित लिखिए।

पाठेतर सक्रियता

आप गर्मी की चिलचिलाती धूप में कभी सप् ़ शफ़र करें तो दूर सड़क पर आपको पानी जैसा दिखाई देगा पर पास पहुँचने पर वहाँ कुछ नहीं होता। अपने जीवन में भी कभी-कभी हम सोचते कुछ हैं, दिखता कुछ है लेकिन वास्तविकता कुछ और होती है। आपके जीवन में घटे ऐसे किसी अनुभव को अपने प्रिय मित्र को पत्र लिखकर अभिव्यक्त कीजिए।

कवि गिरिजाकुमार माथुर की ‘पंद्रह अगस्त’ कविता खोजकर पढ़िए और उस पर चर्चा कीजिए।

आप गर्मी की चिलचिलाती धूप में कभी सप् ़ शफ़र करें तो दूर सड़क पर आपको पानी जैसा दिखाई देगा पर पास पहुँचने पर वहाँ कुछ नहीं होता। अपने जीवन में भी कभी-कभी हम सोचते कुछ हैं, दिखता कुछ है लेकिन वास्तविकता कुछ और होती है। आपके जीवन में घटे ऐसे किसी अनुभव को अपने प्रिय मित्र को पत्र लिखकर अभिव्यक्त कीजिए। कवि गिरिजाकुमार माथुर की ‘पंद्रह अगस्त’ कविता खोजकर पढ़िए और उस पर चर्चा कीजिए।

Chapter 8 kanyadan

कन्यादान

प्रश्न-अभ्यास

1- आपके विचार से माँ ने ऐसा क्यों कहा कि लड़की होना पर लड़की जैसी मत दिखाई देना?

2- ‘आग रोटियाँ सेंकने के लिए है जलने के लिए नहीं’
(क) इन पंक्तियों में समाज में स्त्री की किस स्थिति की ओर संकेत किया गया है?
(ख) माँ ने बेटी को सचेत करना क्यों जरूरी समझा?

3- ‘पाठिका थी वह धुँधले प्रकाश की कुछ तुकों और कुछ लयबद्ध पंक्तियों की’ इन पंक्तियों को पढ़कर लड़की की जो छवि आपके सामने उभरकर आ रही है उसे शब्दबद्ध कीजिए।

4- माँ को अपनी बेटी ‘अंतिम पूँजी’ क्यों लग रही थी?

5- माँ ने बेटी को क्या-क्या सीख दी?

रचना और अभिव्यक्ति

6- आपकी दृष्टि में कन्या के साथ दान की बात करना कहाँ तक उचित है?

पाठेतर सक्रियता

‘स्त्री को सौंदर्य का प्रतिमान बना दिया जाना ही उसका बंधन बन जाता है’μइस विषय पर कक्षा में चर्चा कीजिए।

यहाँ अफगानी कवयित्री मीना किश्वर कमाल की कविता की कुछ पंक्तियाँ दी जा रही हैं। क्या आपको कन्यादान कविता से इसका कोई संबंध दिखाई देता है?

Chapter 9 Sangatkar

संगतकार

प्रश्न-अभ्यास

1- संगतकार के माध्यम से कवि किस प्रकार के व्यक्तियों की ओर संकेत करना चाह रहा है?

2- संगतकार जैसे व्यक्ति संगीत के अलावा और किन-किन क्षेत्रें में दिखाई देते हैं?

3- संगतकार किन-किन रूपों में मुख्य गायक-गायिकाओं की मदद करते हैं?

4- भाव स्पष्ट कीजिएμ और उसकी आवाज में जो एक हिचक साप़् शफ़ सुनाई देती है या अपने स्वर को ऊँचा न उठाने की जो कोशिश है उसे विफलता नहीं उसकी मनुष्यता समझा जाना चाहिए।

5- किसी भी क्षेत्र में प्रसिद्धि पाने वाले लोगों को अनेक लोग तरह-तरह से अपना योगदान देते हैं। कोई एक उदाहरण देकर इस कथन पर अपने विचार लिखिए।

6- कभी-कभी तारसप्तक की ऊँचाई पर पहुँचकर मुख्य गायक का स्वर बिखरता नजर आता है उस समय संगतकार उसे बिखरने से बचा लेता है। इस कथन के आलोक में संगतकार की विशेष भूमिका को स्पष्ट कीजिए।

7- सफलता के चरम शिखर पर पहुँचने के दौरान यदि व्यक्ति लड़खड़ाता है तब उसे सहयोगी किस तरह सँभालते हैं?\

रचना और अभिव्यक्ति

8- कल्पना कीजिए कि आपको किसी संगीत या नृत्य समारोह का कार्यक्रम प्रस्तुत करना है लेकिन आपके सहयोगी कलाकार किसी कारणवश नहीं पहुँच पाएँμ

(क) ऐसे में अपनी स्थिति का वर्णन कीजिए।
(ख) ऐसी परिस्थिति का आप कैसे सामना करेंगे?

9- आपके विद्यालय में मनाए जाने वाले सांस्कृतिक समारोह में मंच के पीछे काम करने वाले सहयोगियों की भूमिका पर एक अनुच्छेद लिखिए।

10- किसी भी क्षेत्र में संगतकार की पंक्ति वाले लोग प्रतिभावान होते हुए भी मुख्य या शीर्ष स्थान पर क्यों नहीं पहुँच पाते होंगे?

पाठेतर सक्रियता

आप पि़् शफ़ल्में तो देखते ही होंगे। अपनी पसंद की किसी एक पि़्शफ़ल्म के आधार पर लिखिए कि उस पि़् फ़ल्म की सफलता में अभिनय करने वाल कलाकारों के अतिरिक्त और किन-किन लोगों का योेेगदान रहा।

आपके विद्यालय में किसी प्रसिद्ध गायिका की गीत प्रस्तुति का आयोजन हैμ
(क) इस संबंध पर सूचना प‘ के लिए एक नोटिस तैयार कीजिए।
(ख) गायिका व उसके संगतकारों का परिचय देने के लिए आलेख (स्क्रिप्ट) तैयार कीजिए।

Chapter 10 Neta Ji ka Chasma

नेताजी का चश्मा

प्रश्न-अभ्यास

1- सेनानी न होते हुए भी चश्मेवाले को लोग कैप्टन क्यों कहते थे?

2- हालदार साहब ने ड्राइवर को पहले चौराहे पर गाड़ी रोकने के लिए मना किया था लेकिन बाद में तुरंत रोकने को कहाμ
(क) हालदार साहब पहले मायूस क्यों हो गए थे?
(ख) मूर्ति पर सरकंडे का चश्मा क्या उम्मीद जगाता है?
(ग) हालदार साहब इतनी-सी बात पर भावुक क्यों हो उठे?

3- आशय स्पष्ट कीजिएμ

फ्बार-बार सोचते, क्या होगा उस कौम का जो अपने देश की खातिर घर-गृहस्थी-जवानी-जिदगी सब कुछ होम देनेवालों पर भी हँसती है और अपने लिए बिकने के मौके ढूँढ़ती है।य्

4- पानवाले का एक रेखाचित्र प्रस्तुत कीजिए।

5- फ्वो लँगड़ा क्या जाएगा प् ़ शफ़ौज में। पागल है पागल!य् कैप्टन के प्रति पानवाले की इस टिप्पणी पर अपनी प्रतिक्रिया लिखिए।

रचना और अभिव्यक्ति

6- निम्नलिखित वाक्य पात्रें की कौन-सी विशेषता की ओर संकेत करते हैंμ
(क) हालदार साहब हमेशा चौराहे पर रफ़कते और नेताजी को निहारते।
(ख) पानवाला उदास हो गया। उसने पीछे मुड़कर मुँह का पान नीचे थूका और सिर झुकाकर अपनी धोती के सिरे से आँखें पोंछता हुआ बोलाμसाहब! कैप्टन मर गया।
(ग) कैप्टन बार-बार मूर्ति पर चश्मा लगा देता था।

7- जब तक हालदार साहब ने कैप्टन को साक्षात् देखा नहीं था तब तक उनके मानस पटल पर उसका कौन-सा चित्र रहा होगा, अपनी कल्पना से लिखिए।

8- कस्बों, शहरों, महानगरों के चौराहों पर किसी न किसी क्षेत्र के प्रसिद्ध व्यक्ति की मूर्ति लगाने का प्रचलन-सा हो गया हैμ
(क) इस तरह की मूर्ति लगाने के क्या उद्देश्य हो सकते हैं?
(ख) आप अपने इलाके के चौराहे पर किस व्यक्ति की मूर्ति स्थापित करवाना चाहेंगे और क्यों?
(ग) उस मूर्ति के प्रति आपके एवं दूसरे लोगों के क्या उत्तरदायित्व होने चाहिए?

9- सीमा पर तैनात प़् शफ़ौजी ही देश-प्रेम का परिचय नहीं देते। हम सभी अपने दैनिक कार्यों में किसी न किसी रूप में देश-प्रेम प्रकट करते हैं_ जैसेμसार्वजनिक संपत्ति को नुकसान न पहुँचाना, पर्यावरण संरक्षण आदि।

अपने जीवन-जगत से जुड़े ऐसे और कार्यों का उल्लेख कीजिए और उन पर अमल भी कीजिए।

10- निम्नलिखित पंक्तियों में स्थानीय बोली का प्रभाव स्पष्ट दिखाई देता है, आप इन पंक्तियों को मानक हिदी में लिखिएμ
कोई गिराक आ गया समझो। उसको चौड़े चौखट चाहिए। तो कैप्टन किदर से लाएगा? तो उसको मूर्तिवाला दे दिया। उदर दूसरा बिठा दिया।

11- ‘भई खूब! क्या आइडिया है।’ इस वाक्य को ध्यान में रखते हुए बताइए कि एक भाषा में दूसरी भाषा के शब्दों के आने से क्या लाभ होते हैं?

भाषा-अध्ययन

12- निम्नलिखित वाक्यों से निपात छाँटिए और उनसे नए वाक्य बनाइएμ
(क) नगरपालिका थी तो कुछ न कुछ करती भी रहती थी।
(ख) किसी स्थानीय कलाकार को ही अवसर देने का निर्णय किया गया होगा।
(ग) यानी चश्मा तो था लेकिन संगमरमर का नहीं था।
(घ) हालदार साहब अब भी नहीं समझ पाए।
(घ) दो साल तक हालदार साहब अपने काम के सिलसिले में उस कस्बे से गुजरते रहे।

Chapter 11 Bal Gobin Bhagat

बालगोबिन भगत

प्रश्न-अभ्यास

1- खेतीबारी से जुड़े गृहस्थ बालगोबिन भगत अपनी किन चारित्रिक विशेषताओं के कारण साधु कहलाते थे?

2- भगत की पुत्रवधू उन्हें अकेले क्यों नहीं छोड़ना चाहती थी?

3- भगत ने अपने बेटे की मृत्यु पर अपनी भावनाएँ किस तरह व्यक्त कीं?

4- भगत के व्यक्तित्व और उनकी वेशभूषा का अपने शब्दों में चित्र प्रस्तुत कीजिए।

5- बालगोबिन भगत की दिनचर्या लोगों के अचरज का कारण क्यों थी?

6- पाठ के आधार पर बालगोबिन भगत के मधुर गायन की विशेषताएँ लिखिए।

7- कुछ मार्मिक प्रसंगों के आधार पर यह दिखाई देता है कि बालगोबिन भगत प्रचलित सामाजिक मान्यताओं को नहीं मानते थे। पाठ के आधार पर उन प्रसंगों का उल्लेख कीजिए।

8- धान की रोपाई के समय समूचे माहौल को भगत की स्वर लहरियाँ किस तरह चमत्कृत कर देती थीं? उस माहौल का शब्द-चित्र प्रस्तुत कीजिए।

रचना और अभिव्यक्ति

9- पाठ के आधार पर बताएँ कि बालगोबिन भगत की कबीर पर श्रद्धा किन-किन रूपों में प्रकट हुई है?

10- आपकी दृष्टि में भगत की कबीर पर अगाध श्रद्धा के क्या कारण रहे होंगे?

11- गाँव का सामाजिक-सांस्कृतिक परिवेश आषाढ़ चढ़ते ही उल्लास से क्यों भर जाता है?

12- फ्ऊपर की तसवीर से यह नहीं माना जाए कि बालगोबिन भगत साधु थे।य् क्या ‘साधु’ की पहचान पहनावे के आधार पर की जानी चाहिए? आप किन आधारों पर यह सुनिश्चित करेंगे कि अमुक व्यक्ति ‘साधु’ है?

13- मोह और प्रेम में अंतर होता है। भगत के जीवन की किस घटना के आधार पर इस कथन का सच सिद्ध करेंगे?

भाषा-अध्ययन

14- इस पाठ में आए कोई दस क्रियाविशेषण छाँटकर लिखिए और उनके भेद भी बताइए।

पाठेतर सक्रियता

पाठ में ऋतुओं के बहुत ही सुंदर शब्द-चित्र उकेरे गए हैं। बदलते हुए मौसम को दर्शाते हुए चित्र/प़् फ़ोटो का संग्रह कर एक अलबम तैयार कीजिए।

Chapter 12 Lakhnavi Andaj

लखनवी अंदाज

प्रश्न-अभ्यास

1- लेखक को नवाब साहब के किन हाव-भावों से महसूस हुआ कि वे उनसे बातचीत करने के लिए तनिक भी उत्सुक नहीं हैं?

2- नवाब साहब ने बहुत ही यत्न से खीरा काटा, नमक-मिर्च बुरका, अंततः सूँघकर ही खिड़की से बाहर फेंक दिया। उन्होंने ऐसा क्यों किया होगा? उनका ऐसा करना उनके कैसे स्वभाव को इंगित करता है?

3- बिना विचार, घटना और पात्रें के भी क्या कहानी लिखी जा सकती है। यशपाल के इस विचार से आप कहाँ तक सहमत हैं?

4- आप इस निबंध को और क्या नाम देना चाहेंगे?

रचना और अभिव्यक्ति

5- (क) नवाब साहब द्वारा खीरा खाने की तैयारी करने का एक चित्र प्रस्तुत किया गया है। इस पूरी प्रक्रिया को अपने शब्दों में व्यक्त कीजिए।
(ख) किन-किन चीजों का रसास्वादन करने के लिए आप किस प्रकार की तैयारी करते हैं?

6- खीरे के संबंध में नवाब साहब के व्यवहार को उनकी सनक कहा जा सकता है। आपने नवाबों की और भी सनकों और शौक के बारे में पढ़ा-सुना होगा। किसी एक के बारे में लिखिए।

7- क्या सनक का कोई सकारात्मक रूप हो सकता है? यदि हाँ तो ऐसी सनकों का उल्लेख कीजिए।

भाषा-अध्ययन

8- निम्नलिखित वाक्यों में से क्रियापद छाँटकर क्रिया-भेद भी लिखिएμ
(क) एक सप् ़ शफ़ेदपोश सज्जन बहुत सुविधा से पालथी मारे बैठे थे।
(ख) नवाब साहब ने संगति के लिए उत्साह नहीं दिखाया।
(ग) ठाली बैठे, कल्पना करते रहने की पुरानी आदत है।
(घ) अकेले सप् ़ शफ़र का वक्त काटने के लिए ही खीरे खरीदे होंगे।
(घ) दोनों खीरों के सिर काटे और उन्हें गोदकर झाग निकाला।
(च) नवाब साहब ने सतृष्ण आँखों से नमक-मिर्च के संयोग से चमकती खीरे की फाँकों की ओर देखा।
(छ) नवाब साहब खीरे की तैयारी और इस्तेमाल से थककर लेट गए।
(ज) जेब से चाकू निकाला।

पाठेतर सक्रियता

‘किबला शौक फरमाएँ’, ‘आदाब-अर्ज---शौक फरमाएँगे’ जैसे कथन शिष्टाचार से जुड़े हैं। अपनी मातृभाषा के शिष्टाचार सूचक कथनों की एक सूची तैयार कीजिए।
‘खीरा---मेदे पर बोझ डाल देता है’ क्या वास्तव में खीरा अपच करता है? किसी भी खाद्य पदार्थ का पच-अपच होना कई कारणों पर निर्भर करता है। बड़ाें से बातचीत कर कारणों का पता लगाइए। खाद्य पदार्थों के संबंध में बहुत-सी मान्यताएँ हैं जो आपके क्षेत्र में प्रचलित होंगी, उनके बारे में चर्चा कीजिए।

पतनशील सामंती वर्ग का चित्रण प्रेमचंद ने अपनी एक प्रसिद्ध कहानी ‘शतरंज के खिलाड़ी’ में किया था और फिर बाद में सत्यजीत राय ने इस पर इसी नाम से एक पि़् शफ़ल्म भी बनाई थी। यह कहानी ढूँढ़कर पढ़िए और संभव हो तो पि़्फ़ल्म भी देखिए।

Chapter 13 Manveeya Karuda Kee Divya Chamak

मानवीय करुणा की दिव्य चमक

प्रश्न-अभ्यास

1- प़् फ़ादर की उपस्थिति देवदार की छाया जैसी क्यों लगती थी?

2- प शफ़ादर बुल्के भारतीय संस्कृति के एक अभिन्न अंग हैं, किस आधार पर ऐसा कहा गया है?

3- पाठ में आए उन प्रसंगों का उल्लेख कीजिए जिनसे प् शफ़ादर बुल्के का हिदी प्रेम प्रकट होता है?

4- इस पाठ के आधार पर प् शफ़ादर कामिल बुल्के की जो छवि उभरती है उसे अपने शब्दों में लिखिए।

5- लेखक ने प् शफ़ादर बुल्के को ‘मानवीय करफ़णा की दिव्य चमक’ क्यों कहा है?

6- प् शफ़ादर बुल्के ने संन्यासी की परंपरागत छवि से अलग एक नयी छवि प्रस्तुत की है, कैसे?

7- आशय स्पष्ट कीजिएμ
(क) नम आँखों को गिनना स्याही फैलाना है।
(ख) प् शफ़ादर को याद करना एक उदास शांत संगीत को सुनने जैसा है।

रचना और अभिव्यक्ति

8- आपके विचार से बुल्के ने भारत आने का मन क्यों बनाया होगा?

9- ‘बहुत सुंदर है मेरी जन्मभूमिμरेम्सचैपल।’μइस पंक्ति में प् ़ शफ़ादर बुल्के की अपनी जन्मभूमि के प्रति कौन-सी भावनाएँ अभिव्यक्त होती हैं? आप अपनी जन्मभूमि के बारे में क्या सोचते हैं?

भाषा-अध्ययन

10- मेरा देश भारत विषय पर 200 शब्दों का निबंध लिखिए।

11- आपका मित्र हडसन एंड्री ऑस्ट्रेलिया में रहता है। उसे इस बार की गर्मी की छुि‘यों के दौरान भारत के पर्वतीय प्रदेशों के भ्रमण हेतु निमंत्रित करते हुए पत्र लिखिए।

12- निम्नलिखित वाक्यों में समुच्यबोधक छाँटकर अलग लिखिएμ
(क) तब भी जब वह इलाहाबाद में थे और तब भी जब वह दिल्ली आते थे।
(ख) माँ ने बचपन में ही घोषित कर दिया था कि लड़का हाथ से गया।
(ग) वे रिश्ता बनाते थे तो तोड़ते नहीं थे।
(घ) उनके मुख से सांत्वना के जादू भरे दो शब्द सुनना एक ऐसी रोशनी से भर देता था जो किसी गहरी तपस्या से जनमती है।
(घ) पिता और भाइयों के लिए बहुत लगाव मन में नहीं था लेकिन वो स्मृति में अकसर डूब जाते।

पाठेतर सक्रियता

प् शफ़ादर बुल्के का ‘अंग्रेजी-हिदी कोश’ उनकी एक महत्त्वपूर्ण देन है। इस कोश को देखिए-समझिए।
प् शफ़ादर बुल्के की तरह ऐसी अनेक विभूतियाँ हुईं हैं जिनकी जन्मभूमि अन्यत्र थी लेकिन कर्मभूमि के रूप में उन्होंने भारत को चुना। ऐसे अन्य व्यक्तियों के बारे में जानकारी एकत्र कीजिए।

कुछ ऐसे व्यक्ति भी हुए हैं जिनकी जन्मभूमि भारत है लेकिन उन्होंने अपनी कर्मभूमि किसी और देश को बनाया है, उनके बारे में भी पता लगाइए।
एक अन्य पहलू यह भी है कि पश्चिम की चकाचौंध से आकर्षित होकर अनेक भारतीय विदेशों की ओर उन्मुख हो रहे हैंμइस पर अपने विचार लिखिए।

Chapter 14 Ek kahani Yah Bhi

एक कहानी यह भी

प्रश्न-अभ्यास

1- लेखिका के व्यक्तित्व पर किन-किन व्यक्तियों का किस रूप में प्रभाव पड़ा?

2- इस आत्मकथ्य में लेखिका के पिता ने रसोई को ‘भटियारखाना’ कहकर क्यों संबोधित किया है?

3- वह कौन-सी घटना थी जिसके बारे में सुनने पर लेखिका को न अपनी आँखों पर विश्वास हो पाया और न अपने कानों पर?

4- लेखिका की अपने पिता से वैचारिक टकराहट को अपने शब्दों में लिखिए।

5- इस आत्मकथ्य के आधार पर स्वाधीनता आंदोलन के परिदृश्य का चित्रण करते हुए उसमें मन्नू जी की भूमिका को रेखांकित कीजिए।

रचना और अभिव्यक्ति

6- लेखिका ने बचपन में अपने भाइयों के साथ गिल्ली डंडा तथा पतंग उड़ाने जैसे खेल भी खेले कितु लड़की होने के कारण उनका दायरा घर की चारदीवारी तक सीमित था। क्या आज भी लड़कियों के लिए स्थितियाँ ऐसी ही हैं या बदल गई हैं, अपने परिवेश के आधार पर लिखिए।

7- मनुष्य के जीवन में आस-पड़ोस का बहुत महत्त्व होता है। परंतु महानगरों में रहने वाले लोग प्रायः ‘पड़ोस कल्चर’ से वंचित रह जाते हैं। इस बारे में अपने विचार लिखिए।

8- लेखिका द्वारा पढ़े गए उपन्यासों की सूची बनाइए और उन उपन्यासों को अपने पुस्तकालय में खोजिए।

9- आप भी अपने दैनिक अनुभवों को डायरी में लिखिए।
 

भाषा-अध्ययन

10- इस आत्मकथ्य में मुहावरों का प्रयोग करके लेखिका ने रचना को रोचक बनाया है। रेखांकित मुहावरों को ध्यान में रखकर कुछ और वाक्य बनाएँμ
(क) इस बीच पिता जी के एक निहायत दकियानूसी मित्र ने घर आकर अच्छी तरह पिता जी की लू उतारी।
(ख) वे तो आग लगाकर चले गए और पिता जी सारे दिन भभकते रहे।
(ग) बस अब यही रह गया है कि लोग घर आकर थू-थू करके चले जाएँ।
(घ) पत्र पढ़ते ही पिता जी आग-बबूला।

पाठेतर सक्रियता

इस आत्मकथ्य से हमें यह जानकारी मिलती है कि कैसे लेखिका का परिचय साहित्य की अच्छी पुस्तकों से हुआ। आप इस जानकारी का लाभ उठाते हुए अच्छी साहित्यिक पुस्तकें पढ़ने का सिलसिला शुरू कर सकते हैं। कौन जानता है कि आप में से ही कोई अच्छा पाठक बनने के साथ-साथ अच्छा रचनाकार भी बन जाए। लेखिका के बचपन के खेलों में लँगड़ी टाँग, पकड़म-पकड़ाई और काली-टीलो आदि शामिल थे। क्या आप भी यह खेल खेलते हैं। आपके परिवेश में इन खेलों के लिए कौन-से शब्द प्रचलन में हैं। इनके अतिरिक्त आप जो खेल खेलते हैं उन पर चर्चा कीजिए। स्वतंत्रता आंदोलन में महिलाओं की भी सक्रिय भागीदारी रही है। उनके बारे में जानकारी प्राप्त कीजिए और उनमें से किसी एक पर प्रोजेक्ट तैयार कीजिए।

Chapter 15 Estri Virodhi Kutarko Ka Khundan

स्त्री-शिक्षा के विरोधी कुतर्कों का खंडन

प्रश्न-अभ्यास

1- कुछ पुरातन पंथी लोग स्त्रियों की शिक्षा के विरोधी थे। द्विवेदी जी ने क्या-क्या तर्क देकर स्त्री-शिक्षा का समर्थन किया?

2- ‘स्त्रियों को पढ़ाने से अनर्थ होते हैं’μकुतर्कवादियों की इस दलील का खंडन द्विवेदी जी ने कैसे किया है, अपने शब्दों में लिखिए।

3- द्विवेदी जी ने स्त्री-शिक्षा विरोधी कुतर्कों का खंडन करने के लिए व्यंग्य का सहारा लिया है-जैसे ‘यह सब पापी पढ़ने का अपराध है। न वे पढ़तीं, न वे पूजनीय पुुरफ़षों का मुकाबला करतीं।’ आप ऐसे अन्य अंशों को निबंध में से छाँटकर समझिए और लिखिए।

4- पुराने समय में स्त्रियों द्वारा प्राकृत भाषा में बोलना क्या उनके अपढ़ होने का सबूत हैμपाठ के आधार पर स्पष्ट कीजिए।

5- परंपरा के उन्हीं पक्षों को स्वीकार किया जाना चाहिए जो स्त्री-पुरफ़ष समानता को बढ़ाते हों-तर्क सहित उत्तर दीजिए।

6- तब की शिक्षा प्रणाली और अब की शिक्षा प्रणाली में क्या अंतर है? स्पष्ट करें।

रचना और अभिव्यक्ति

7- महावीरप्रसाद द्विवेदी का निबंध उनकी दूरगामी और खुली सोच का परिचायक है, कैसे?

8- द्विवेदी जी की भाषा-शैली पर एक अनुच्छेद लिखिए।

भाषा-अध्ययन

9- निम्नलिखित अनेकार्थी शब्दों को ऐसे वाक्यों में प्रयुक्त कीजिए जिनमें उनके एकाधिक अर्थ स्पष्ट होंμ
चाल, दल, पत्र, हरा, पर, फल, कुल पाठेतर सक्रियता अपनी दादी, नानी और माँ से बातचीत कीजिए और (स्त्री-शिक्षा संबंधी) उस समय की स्थितियों का पता लगाइए और अपनी स्थितियों से तुलना करते हुए निबंध लिखिए। चाहें तो उसके साथ तसवीरें भी चिपकाइए। लड़कियों की शिक्षा के प्रति परिवार और समाज में जागरूकता आएμइसके लिए आप क्या-क्या करेंगे? स्त्री-शिक्षा पर एक पोस्टर तैयार कीजिए। स्त्री-शिक्षा पर एक नुक्कड़ नाटक तैयार कर उसे प्रस्तुत कीजिए।

Chapter 16 Noubat Khane Ki Ebadat

नौबतखाने में इबादत

प्रश्न-अभ्यास

1- शहनाई की दुनिया में डुमराँव को क्यों याद किया जाता है?

2- बिस्मिल्ला खाँ को शहनाई की मंगलध्वनि का नायक क्यों कहा गया है?

3- सुषिर-वाद्यों से क्या अभिप्राय है? शहनाई को ‘सुषिर वाद्यों में शाह’ की उपाधि क्यों दी गई होगी?

4- आशय स्पष्ट कीजिएμ
(क) ‘फटा सुर न बख्शें। लुंगिया का क्या है, आज फटी है, तो कल सी जाएगी।’
(ख) ‘मेरे मालिक सुर बख्श दे। सुर में वह तासीर पैदा कर कि आँखों से सच्चे मोती की तरह अनगढ़ आँसू निकल आएँ।’

5- काशी में हो रहे कौन-से परिवर्तन बिस्मिल्ला खाँ को व्यथित करते थे?

6- पाठ में आए किन प्रसंगों के आधार पर आप कह सकते हैं किμ
(क) बिस्मिल्ला खाँ मिली-जुली संस्कृति के प्रतीक थे।
(ख) वे वास्तविक अर्थों में एक सच्चे इनसान थे।

7- बिस्मिल्ला खाँ के जीवन से जुड़ी उन घटनाओं और व्यक्तियों का उल्लेख करें जिन्होंने उनकी संगीत साधना को समृद्ध किया?

रचना और अभिव्यक्ति

8- बिस्मिल्ला खाँ के व्यक्तित्व की कौन-कौन सी विशेषताओं ने आपको प्रभावित किया?

9- मुहर्रम से बिस्मिल्ला खाँ के जुड़ाव को अपने शब्दों में लिखिए।

10- बिस्मिल्ला खाँ कला के अनन्य उपासक थे, तर्क सहित उत्तर दीजिए।

भाषा अध्ययन

11- निम्नलिखित मिश्र वाक्यों के उपवाक्य छाँटकर भेद भी लिखिएμ
(क) यह जरूर है कि शहनाई और डुमराँव एक-दूसरे के लिए उपयोगी हैं।
(ख) रीड अंदर से पोली होती है जिसके सहारे शहनाई को फूँका जाता है।
(ग) रीड नरकट से बनाई जाती है जो डुमराँव में मुख्यतः सोन नदी के किनारों पर पाई जाती है।
(घ) उनको यकीन है, कभी खुदा यूँ ही उन पर मेहरबान होगा।
(घ) हिरन अपनी ही महक से परेशान पूरे जंगल में उस वरदान को खोजता है जिसकी गमक उसी में समाई है।
(च) खाँ साहब की सबसे बड़ी देन हमें यही है कि पूरे अस्सी बरस उन्होंने संगीत को संपूर्णता व एकाधिकार से सीखने की जिजीविषा को अपने भीतर जिंदा रखा।

12- निम्नलिखित वाक्यों को मिश्रित वाक्यों में बदलिएμ
(क) इसी बालसुलभ हँसी में कई यादें बंद हैं।
(ख) काशी में संगीत आयोजन की एक प्राचीन एवं अद्भुत परंपरा है।
(ग) धत्! पगली ई भारतरत्न हमको शहनईया पे मिला है, लुंगिया पे नाहीं।
(घ) काशी का नायाब हीरा हमेशा से दो कौमों को एक होकर आपस में भाईचारे के साथ रहने की प्रेरणा देता रहा।\

पाठेतर सक्रियता

कल्पना कीजिए कि आपके विद्यालय में किसी प्रसिद्ध संगीतकार के शहनाई वादन का कार्यक्रम आयोजित किया जा रहा है। इस कार्यक्रम की सूचना देते हुए बुलेटिन बोर्ड के लिए नोटिस बनाइए। आप अपने मनपसंद संगीतकार के बारे में एक अनुच्छेद लिखिए। हमारे साहित्य, कला, संगीत और नृत्य को समृद्ध करने में काशी (आज के वाराणसी) के योगदान पर चर्चा कीजिए। काशी का नाम आते ही हमारी आँखों के सामने काशी की बहुत-सी चीजें उभरने लगती हैं, वे कौन-कौन सी हैं?

Chapter 17 Sanskrity

संस्कृति

1- लेखक की दृष्टि में ‘सभ्यता’ और ‘संस्कृति’ की सही समझ अब तक क्यों नहीं बन पाई है?

2- आग की खोज एक बहुत बड़ी खोज क्यों मानी जाती है? इस खोज के पीछे रही प्रेरणा के मुख्य स्रोत क्या रहे होंगे?

3- वास्तविक अर्थों में ‘संस्कृत व्यक्ति’ किसे कहा जा सकता है?

4- न्यूटन को संस्कृत मानव कहने के पीछे कौन से तर्क दिए गए हैं? न्यूटन द्वारा प्रतिपादित सिद्धांतों एवं ज्ञान की कई दूसरी बारीकियों को जानने वाले लोग भी न्यूटन की तरह संस्कृत नहीं कहला सकते, क्यों?

5- किन महत्त्वपूर्ण आवश्यकताओं की पूर्ति के लिए सुई-धागे का आविष्कार हुआ होगा?

6- फ्मानव संस्कृति एक अविभाज्य वस्तु है।य् किन्हीं दो प्रसंगाें का उल्लेख कीजिए जब दवज जव इम तमचनइसपेीमक
(क) मानव संस्कृति को विभाजित करने की चेष्टाएँ की गईं।
(ख) जब मानव संस्कृति ने अपने एक होने का प्रमाण दिया।

7- आशय स्पष्ट कीजिएμ
(क) मानव की जो योग्यता उससे आत्म-विनाश के साधनों का आविष्कार कराती है, हम उसे उसकी संस्कृति कहें या असंस्कृति? रचना और अभिव्यक्ति

8- लेखक ने अपने दृष्टिकोण से सभ्यता और संस्कृति की एक परिभाषा दी है। आप सभ्यता और संस्कृति के बारे में क्या सोचते हैं, लिखिए।

भाषा-अध्ययन

9- निम्नलिखित सामासिक पदों का विग्रह करके समास का भेद भी लिखिएμ
गलत-सलत आत्म-विनाश
महामानव पददलित
हिदू-मुसलिम यथोचित
सप्तर्षि सुलोचना
पाठेतर सक्रियता
‘स्थूल भौतिक कारण ही आविष्कारों का आधार नहीं है।’ इस विषय पर वाद-विवाद प्रतियोगिता का आयोजन कीजिए।
उन खोजों और आविष्कारों की सूची तैयार कीजिए जो आपकी नजर में बहुत महत्त्वपूर्ण हैं?
शब्द-संपदा
ौ छब्म्त्ज्
आध्यात्मिक - परमात्मा या आत्मा से संबंध रखने वाला मन से संबंध रखने वाला
साक्षात - आँखों के सामने, प्रत्यक्ष, सीधे
आविष्कर्ता - आविष्कार करने वाला
परिष्कृत - जिसका परिष्कार किया गया हो, शुद्ध किया हुआ, साप्
़ शफ़ किया हुआ

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(Book) National Geographic Animal Encyclopedia

Book Details:

Hardcover: 304 pages

Publisher: National Geographic Children's Books (23 October 2012)

Language: English

ISBN-10: 1426310226

ISBN-13: 978-1426310225

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NCERT Social Science Question Paper (Class - 10)

(Political Science) : Chapter 1 Power Sharing

Question 1: What are the different forms of power sharing in modern democracies? Give an example of each of these.

Question 2: State one prudential reason and one moral reason for power sharing with an example from the Indian context.

Question 3: After reading this chapter, three students drew different conclusions. Which of these do you agree with and why? Give your reasons in about 50 words.

Question 4: The Mayor of Merchtem, a town near Brussels in Belgium, has defended a ban on speaking French in the town’s schools. He said that the ban would help all non-Dutch speakers integrate in this Flemish town. Do you think that this measure is in keeping with the spirit of Belgium’s power sharing arrangements? Give your reasons in about 50 words.

Question 5: Read the following passage and pick out any one of the prudential reasons for power sharing offered in this.

"We need to give more power to the panchayats to realise the dream of Mahatma Gandhi and the hopes of the makers of our Constitution. Panchayati Raj establishes true democracy. It restores power to the only place where power belongs in a democracy − in the hands of the people. Given power to panchayats is also a way to reduce corruption and increase administrative efficiency. When people participate in the planning and implementation of developmental schemes, they would naturally exercise greater control over these schemes. This would eliminate the corrupt middlemen. Thus, Panchayati Raj will strengthen the foundations of our democracy."

Question 6: Different arguments are usually put forth in favour of and against power sharing.Identify those which are in favour of power sharing and select the answer using thecodes given below? Power sharing:

A. reduces conflict among different communities
B. decreases the possibility of arbitrariness
C. delays decision making process
D. accommodates diversities
E. increases instability and divisiveness
F. promotes people’s participation in government
G. undermines the unity of a country

Question 7: Consider the following statements about power sharing arrangements in Belgium and Sri Lanka.

Α. In Belgium, the Dutch-speaking majority people tried to impose their domination on the minority French-speaking community.
B. In Sri Lanka, the policies of the government sought to ensure the dominance of the Sinhala-speaking majority.
C. The Tamils in Sri Lanka demanded a federal arrangement of power sharing to protect their culture, language and equality of opportunity in education and jobs.
D. The transformation of Belgium from unitary government to a federal one prevented a possible division of the country on linguistic lines.

Which of the statements given above are correct?

Question 8:  Match list I (forms of power sharing) with List II (forms of government) and select the correct answer using the codes given below in the lists:

Question 9: Consider the following two statements on power sharing and select the answer using the codes given below:

A. Power sharing is good for democracy.
B. It helps to reduce the possibility of conflict between social groups.

Which of these statements are true and false?

(Political Science) : Chapter 2 Federalism

Question 1: Locate the following States on a blank outline political map of India:Manipur, Sikkim, Chhattisgarh and Goa

Question 2:  Identify and shade three federal countries (other than India) on a blank outline political map of the world.

Question 3: Point out one feature in the practice of federalism in India that is similar to and one feature that is different from that of Belgium.

Question 4: What is the main difference between a federal form of government and a unitary one? Explain with an example.

Question 5: State any two differences between the local government before and after the constitutional amendment in 1992.

Question 6: Fill in the blanks:

Since the United States is a ____________________ type of federation, all the
constituent States have equal powers and States are _______________ vis-a -vis the
federal government. But India is a _________________ type of federation and some
States have more power than others. In India, the ___________________ government has more powers.

Question 7: Here are three reactions to the language policy followed in India. Give an argument and an example to support any of these positions.
Sangeeta: The policy of accommodation has strengthened national unity. Arman: Language-based States have divided us by making everyone conscious of their language. Harish: This policy has only helped to consolidate the dominance of English over all other languages.

Question 8: The distinguishing feature of a federal government is:

(a) National government gives some powers to the provincial governments.
(b) Power is distributed among the legislature, executive and judiciary.
(c) Elected officials exercise supreme power in the government.
(d) Governmental power is divided between different levels of government.

Question 9: A few subjects in various Lists of the Indian Constitution are given here. Group them under the Union, State and Concurrent Lists as provided in the table below.

A. Defence
Β. Police
C. Agriculture
D. Education
E. Banking
F. Forests
G. Communications 

Question 10:  Examine the following pairs that give the level of government in India and the powers of the government at that level to make laws on the subjects mentioned against each. Which of the following pairs is not correctly matched? 

Question 11: Match List I with List II and select the correct answer using the codes given below the lists:

Question 12: Consider the following statements.

A. In a federation the powers of the federal and provincial governments are clearly demarcated.
B. India is a federation because the powers of the Union and State Governments are specified in the Constitution and they have exclusive jurisdiction on their respective subjects.
C. Sri Lanka is a federation because the country is divided into provinces.
D. India is no longer a federation because some powers of the states have been devolved to the local government bodies. Which of the statements given above are correct?

(Political Science) : Chapter 3 Democracy and Diversity

Question 1: Discuss three factors that determine the outcomes of politics of social divisions.

Question 2: When does a social difference become a social division?

Question 3: How do social divisions affect politics? Give two examples.

Question 4: ________________ social differences create possibilities of deep social divisions andtensions.
________________ social differences do not usually lead to conflicts.

Question 5: In dealing with social divisions which one of the following statements is NOT correct about democracy?

(a) Due to political competition in a democracy, social divisions get reflected in politics.
(b) In a democracy it is possible for communities to voice their grievances in a peaceful manner.
(c) Democracy is the best way to accommodate social diversity.
(d) Democracy always leads to disintegration of society on the basis of social divisions.

Question 6: onsider the following three statements.

Α. Social divisions take place when social differences overlap.
Β. It is possible that a person can have multiple identities.
C. Social divisions exist in only big countries like India.

Which of the statements is/are correct?

Question 7:Arrange the following statements in a logical sequence and select the right answers by using the code given below.

Α. But all political expression of social divisions need not be always dangerous.
B. Social divisions of one kind or the other exist in most countries.
C. Parties try to win political support by appealing to social divisions.
D. Some social differences may result in social divisions.

Question 8: Among the following, which country suffered disintegration due to political fights on the basis of religious and ethnic identities?

(a) Belgium
(b) India
(c) Yugoslavia
(d) Netherlands

Question 9: Read the following passage from a famous speech by Martin Luther king Jr. in 1963. Which social division is he talking about? What are his aspirations and anxieties? Do you see a relationship between this speech and the incident in Mexico Olympics mentioned in this chapter?

"I have a dream that my four little children will one day live in a nation where they will not be judged by the colour of their skin but by the content of their character. Let freedom ring − when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God’s children − back men and white men, Jews and Gentiles, Protestants and Catholics − will be able to join hands and sing in the words of the old Negro spiritual: 'Free at last! Free at last! Thank God Almighty, we are free at last!' I have a dream that one day this nation will rise up and live out the true meaning of its creed: 'we hold these truths to be self-evident: that all men are created equal'."

(Political Science) : Chapter 4 Gender Religion and Caste

Question 1: Mention different aspects of life in which women are discriminated or disadvantaged in India.

Question 2: State different forms of communal politics with one example each.

Question 3: State how caste inequalities are still continuing in India.

Question 4: State two reasons to say that caste alone cannot determine election results in India.

Question 5: What is the status of women’s representation in India’s legislative bodies?

Question 6: Mention any two constitutional provisions that make India a secular state.

Question 7: When we speak of gender divisions, we usually refer to:

(a) Biological difference between men and women
(b) Unequal roles assigned by the society to men and women
(c) Unequal child sex ratio
(d) Absence of voting rights for women in democracies

Question 8: In India seats are reserved for women in

(a) Lok Sabha
(b) State Legislative Assemblies
(c) Cabinets
(d) Panchayati Raj bodies

Question 9: Consider the following statements on the meaning of communal politics. Communal politics is based on the belief that:

Α. One religion is superior to that of others.
Β. People belonging to different religions can live together happily as equal citizens.
C. Followers of a particular religion constitute one community.
D. State power cannot be used to establish the domination of one religious group over others.

Question 10: Which among the following statements about India’s Constitution is wrong? It

(a) prohibits discrimination on grounds of religion
(b) gives official status to one religion
(c) provides to all individuals freedom to profess any religion
(d) ensures equality of citizens within religious communities

Question 11: Social divisions based on ______________ are peculiar to India.

Question 12: Match List I with List II and select the correct answer using the codes given below the Lists:

 (Political Science) : Chapter 5 popular Struggles And Movement

Question 1: In what ways do pressure groups and movements exert influence on politics?

Question 2: Describe the forms of relationship between pressure groups and political parties?

Question 3:  Explain how the activities of pressure groups are useful in the functioning of a democratic government.

Question 4: What is a pressure group? Give a few examples.

Question 5: What is the difference between a pressure group and a political party?

Question 6: Organisations that undertake activities to promote the interests of specific socialsections such as workers, employees, teachers, and lawyers are called_____________ groups.

Question 7: Which among the following is the special feature that distinguishes a pressure group from a political party?

(a) Parties take political stances, while pressure groups do not bother about political issues.
(b) Pressure groups are confined to a few people, while parties involve larger number of people.
(c) Pressure groups do not seek to get into power, while political parties do.
(d) Pressure groups do not seek to mobilise people, while parties do.

Question 8: Match List I (organisations and struggles) with List II and select the correct answer using the codes given below the lists:

Question  9: Match List I with list II and select the correct answer using the codes given below the lists:

Question 10: Consider the following statements about pressure groups and parties.

Α. Pressure groups are the organised expression of the interests and views of specific social sections.
Β. Pressure groups take positions on political issues.
C. All pressure groups are political parties.

Which of the statements given above are correct?

Question 11: Mewat is one of the most backward areas in Haryana. It used to be a part of two districts, Gurgaon and Faridabad. The people of Mewat felt that the area will get better attention if it were to become a separate district. But political parties were indifferent to this sentiment. The demand for a separate district was raised by Mewat Educational and Social Organisation and Mewat Saksharta Samiti in 1996. Later, Mewat Vikas Sabha was founded in 2000 and carried out a series of public awareness campaigns. This forced both the major parties, Congress and the Indian National Lok Dal, to announce their support for the new district before the assembly elections held in February 2005. The new district came into existence in July 2005. In this example what is the relationship that you observe among movement, political parties and the government? Can you think of an example that shows a relationship different from this one?

(Political Science) : Chapter 6 Political Parties

Question 1: State the various functions political parties perform in a democracy.

Question 2: What are the various challenges faced by political parties?

Question 3: Suggest some reforms to strengthen parties so that they perform their functions well?

Question 4: What is a political party?

Question 5: What are the characteristics of a political party?

Question 6: A group of people who come together to contest elections and hold power in the government is called a ______________________.

Question 7: Match List I (organisations and struggles) with List II and select the correct answer using the codes given below the lists:

Question 8:  Who among the following is the founder of the Bahujan Samaj Party?

Α. Kanshi Ram
Β. Sahu Maharaj
C. Β.R. Ambedker
D. Jotiba Phule

Question 9: What is the guiding philosophy of the Bharatiya Janata Party?

Α. Bahujan Samaj
Β. Revolutionary democracy
C. Integral humanism
D. Modernity

Question 10: Consider the following statements on parties.

Α. Political parties do not enjoy much trust among the people.
Β. Parties are often rocked by scandals involving top party leaders.
C. Parties are not necessary to run governments.

Which of the statements given above are correct?

Question 11: Read the following passage and answer the questions given below:

Muhammad Yunus is a famous economist of Bangladesh. He received several international honours for his efforts to promote economic and social development for the benefit of the poor. He and the Grameen Bank he started, jointly received the Noble Peace Prize for 2006. In February 2007, he decided to launch a political party and contest in the parliamentary elections. His objective was to foster proper leadership, good governance and build a new Bangladesh. He felt that only a political party different from the traditional ones would bring about new political culture. His party would be democratic from the grassroots level. The launching of the new party, called Nagarik Shakti (Citizens’ Power), has caused a

 stir among the Bangladeshis. While many welcomed his decisions, some did not like it. "Now I think Bangladesh will have a chance to choose between good and bad and eventually have a good government," said Shahedul Islam, a government official. "That government, we hope, would not only keep itself away from corruption but also make fighting corruption and black money a top priority." But leaders of traditional political parties who dominated the country’s politics for decades were apprehensive. "There was no debate (over him) winning the Novel, but politics is different − very challenging and often controversial," said a senior leader of the Bangladesh Nationalist Party. Some others were highly critical. They asked why he was rushing into politics. "Is he being planted in politics by mentors from outside the country," asked one political observer. Do you think Yunus made a right decision to float a new political party? Do you agree with the statements and fears expressed by various people? How do you want this new party organised to make it different from other parties? If you were the one to begin this political party how would you defend it?

(Political Science) : Chapter 7 Outcomes Of Democracy

Question 1: How does democracy produce an accountable, responsive and legitimate government?

Question 2: What are the conditions under which democracies accommodate social diversities?

Question 3: Give arguments to support or oppose the following assertions: Industrialised countries can afford democracy but the poor need dictatorship
to become rich. Democracy can’t reduce inequality of incomes between different citizens. Government in poor countries should spend less on poverty reduction, health, education and spend more on industries and infrastructure. In democracy all citizens have one vote, which means that there is absence of any domination and conflict.

Question 4: Identify the challenges to democracy in the following descriptions. Also suggest policy/institutional mechanism to deepen democracy in the given situations: Following a High Court directive a temple in Orissa that had separate entry doors for dalits and non-dalits allowed entry for all from the same door. A large number of farmers are committing suicide in different states of India.

Following allegation of killing of three civilians in Gandwara in a fake encounter by Jammu and Kashmir police, an enquiry has been ordered.

Question 5: In the context of democracies, which of the following ideas is correct − democracies have successfully eliminated:

Α. conflicts among people
Β. economic inequalities among people
C. differences of opinion about how marginalised sections are to be treated
D. the idea of political inequality

Question 6: In the context of assessing democracy which among the following is odd one out.

Democracies need to ensure:

Α. free and fair elections
Β. dignity of the individual
C. majority rule
D. equal treatment before law

Question 7: Studies on political and social inequalities in democracy show that

Α. democracy and development go together
Β. inequalities exist in democracies
C. inequalities do not exist under dictatorship
D. dictatorship is better than democracy

Question 8: Read the passage below:

Nannu is a daily wage earner. He lives in Welcome Mazdoor Colony, a slum habitation in East Delhi. He lost his ration card and applied for a duplicate one in January 2004. He made several rounds to the local Food & Civil Supplies office for the next three months. But the clerks and officials would not even look at him, leave alone do his job or bother to tell him the status of his application. Ultimately, he filed an application under the Right to Information Act asking for the daily progress made on his application, names of the officials, who were supposed to act on his application and what action would be taken against these officials for their inaction. Within a week of filing application under the Right to Information Act, he was visited by an inspector from the Food Department, who informed him that the card had been made and he could collect it from the office. When Nannu went to collect his card next day, he was given a very warm treatment by the Food & Supply Officer (FSO), who is the head of a Circle. The FSO offered him tea and requested him to withdraw his application under the Right to Information, since his work had already been done. What does Nannu’s example show? What impact did Nannu’s action have on officials? Ask your parents their experiences when they approach government officials to attend to their problems.

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(Book) General Knowledge Encyclopedia

Book Details:

Paperback: 96 pages

Publisher: General Press; Tenth Edition edition (1 July 2005)

Language: English

ISBN-10: 9380914199

ISBN-13: 978-9380914190

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NCERT Mathematics Question Paper (Class - 10)

:: Chapter 1: Number System ::

Exercise 1.1

Question 1. Use Euclid’s division algorithm to find the HCF of

(i) 135 and 225
(ii) 196 and 38220
(iii) 867 and 255

Question 2: Show that any positive odd integer is of the form 6q + 1, or 6q + 3, or 6q + 5, where q is some integer.

Question 3. An army contingent of 616 members is to march behind an army band of 32 members in a parade. The two groups are to march in the same number of columns. What is the maximum number of columns iwhich they can march?

Question 4. Use Euclid’s division lemma to show that the square of any positive integer is either of the form 3m or 3m + 1 for some integer m

Question 5. Use Euclid’s division lemma to show that the cube of any positive integer is of the form 9m, 9m + 1 or 9m + 8.

Exercise 1.2

Question 1. Express each number as a product of its prime factors: (i) 140 (ii) 156 (iii) 3825 (iv) 5005 (v) 7429

Question 2. Find the LCM and HCF of the following pairs of integers and verify that LCM × HCF = product of the two numbers. 26 and 91 (ii) 510 and 92 (iii) 336 and 54

Question 3. Find the LCM and HCF of the following integers by applying the prime factorization method.

(i) 12, 15 and 21
(ii) 17, 23 and 29
(iii) 8, 9 and 25

Question 4. Given that HCF (306, 657) = 9, find LCM (306, 657).

Question 5. Check whether 6n can end with the digit 0 for any natural number n.

Question 6. Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers.

Question 7. There is a circular path around a sports field. Sonia takes 18 minutes to drive one round of the field, while Ravi takes 12 minutes for the same. Suppose they both start at the same point and at the same time, and go in the same direction. After how many minutes will they meet again at the starting point?

Exercise 1.3

Question 1. Prove that √5 is irrational.

Question 2. Prove that 3 + 2√5 is irrational.

Question 3. Prove that the following are irrationals: (i) 1/√2 (ii) 7√5 (iii) 6 + √2

Exercise 1.4

Question 1. Without actually performing the long division, state whether the following rational numbers will have a terminating decimal expansion or a non-terminating repeating decimal expansion:

(i)13/3125
(ii)17/8
(iii)64/455
(iv)15/1600
(v)29/343
(vi)23/2³*5²
(vii)129/2²* 57* 75
(viii)6/15
(ix)35/50
(x)77/210

Question 2. Write down the decimal expansions of those rational numbers in Question 1 above which have terminating decimal expansions.

(i)13/3125 = 0.009375
(ii)17/8
(iii)64/455 none- terminating
(iv)15/1600
(v)29/343 it is none – terminating
(vi)23/2³*5² = 23/200
(vii)129/2²* 57*75 it is none terminating
(viii) 6/15 = 2/5 = 0.4
(ix)35/50

Question 3. The following real numbers have decimal expansions as given below. In each case, decide whether they are rational or not. If they are rational, and of the form p , q you say about the prime factors of q?

:: Chapter 2: Polynomial ::

Exercise 2.1

Question 1. The graphs of y = p(x) are given in Fig. 2.10 below, for some polynomials p(x). Find the number of zeroes of p(x), in each case.

Exercise 2.2

Question 1. Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.
(iii) 4u² + 8u

Question 1. Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.

(i) x² – 2x – 8
(ii) 4s² – 4s + 1
(iii) 6x² – 3 – 7x
(v) t² – 15
(vi)3x² – x – 4

Question 2. Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively.

(i)1/4 , -1 (ii) √2 , 1/3 (iii) 0, √5 (iv) 1,1 (v) -1/4 ,1/4 (vi) 4,1

Exercise 2.3

1. Divide the polynomial p(x) by the polynomial g(x) and find the quotient and remainder in each of the following :

Question 2. Check whether the first polynomial is a factor of the second polynomial by dividing the second polynomial by the first polynomial:

Question 3. Obtain all other zeroes of 3x4 + 6x3 – 2x2 – 10x – 5, if two of its zeroes are √(5/3) and - √(5/3)

Question 4. On dividing x3 – 3x2 + x + 2 by a polynomial g(x), the quotient and remainder were x – 2 and –2x + 4, respectively. Find g(x).

Question 5. Give examples of polynomials p(x), g(x), q(x) and r(x), which satisfy the division algorithm

:: 3: MATRIX ::

Exercise 3.1

Question 1. Aftab tells his daughter, “Seven years ago, I was seven times as old as you were then .Also, three years from now, I shall be three times as old as you will be.” (Isn’t this interesting?) Represent this situation algebraically and graphically.

Question 2. The coach of a cricket team buys 3 bats and 6 balls for Rs 3900. Later, she buys another bat and 2 more balls of the same kind for Rs 1300. Represent this situation algebraically and geometrically.

Question 3. The cost of 2 kg of apples and 1kg of grapes on a day was found to be Rs 160. After a month, the cost of 4 kg of apples and 2 kg of grapes is Rs 300. Represent the situation algebraically and geometrically.

Exercise 3.2

Question 1 (ii). 5 pencils and 7 pens together cost Rs 50, whereas 7 pencils and 5 pens together cost Rs 46. Find the cost of one pencil and that of one pen

Question 2. On comparing the ratios a1/a2 , b1/b2 and c1/c2, find out whether the lines representing the following pairs of linear equations intersect at a point, are parallel or coincident:

Question 3. On comparing the ratios a1/a2 , b1/b2 and c1/c2 find out whether the following pair of linear equations are consistent, or inconsistent.

(i) 3x + 2y = 5 ; 2x – 3y = 7
(ii) 2x – 3y = 8 ; 4x – 6y = 9
(iii) 3/2x + 5/3 y = 7 ; 9x – 10y = 14
(iv) 5x – 3y = 11 ; – 10x + 6y = –22
(v)4/3x + 2y =8 ; 2x + 3y = 12
(i) 3x + 2y = 5 ; 2x – 3y = 7

Question 4. Which of the following pairs of linear equations are consistent/inconsistent? If consistent, obtain the solution graphically:

Question 5. Half the perimeter of a rectangular garden, whose length is 4 m more than its width, is 36 m. Find the dimensions of the garden.

Question 6. Given the linear equation 2x + 3y – 8 = 0, write another linear equation in two variables such that the geometrical representation of the pair so formed is:

Question 7. Draw the graphs of the equations x – y + 1 = 0 and 3x + 2y – 12 = 0. Determine the coordinates of the vertices of the triangle formed by these lines and the x-axis, and shade the triangular region.

Exercise 3.3

Question 1. Solve the following pair of linear equations by the substitution method.

(i) x + y = 14 ; x – y = 4
(ii) s – t = 3 ; s/3 + t/2 = 6
(iii) 3x – y = 3 ; 9x – 3y = 9
(iv) 0.2x + 0.3y = 1.3 ; 0.4x + 0.5y = 2.3
(v)√2 x+ √3y = 0 ; √3 x - √8y = 0 (vi)3/2 x - 5/3y = -2 ; x/3 + y/2 = 13/6

Question 2. Solve 2x + 3y = 11 and 2x – 4y = – 24 and hence find the value of ‘m’ for which y =mx + 3.

Question 3. Form the pair of linear equations for the following problems and find their solution by substitution method.

(i) The difference between two numbers is 26 and one number is three times the other. Find them.
(ii) The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.
(iii) The coach of a cricket team buys 7 bats and 6 balls for Rs 3800. Later, she buys 3 bats and 5 balls for Rs 1750. Find the cost of each bat and each ball

Exercise 3.4

Question 1. Solve the following pair of linear equations by the elimination method and the substitution method:

x + y =5 and 2x –3y = 4
3x + 4y = 10 and 2x – 2y = 2
3x – 5y – 4 = 0 and 9x = 2y + 7
x/2 + 2y /3 = - 1 and x – y/3 = 3

Question 2. Form the pair of linear equations in the following problems, and find their solutions (if they exist) by the elimination method:

(i) If we add 1tothe numerator and subtract 1fromthe denominator, a fractionreduces to 1. It becomes1/2 if we only add 1 to the denominator.What is the raction?
(ii) Five years ago, Nuri was thrice as old as Sonu. Ten years later, Nuri will be twice as old as Sonu. How old are Nuri and Sonu?
(iii) The sum of the digits of a t

Exercise 3.5

Question 1. Which of the following pairs of linear equations has unique solution, no solution, or infinitely many solutions In case there is a unique solution, find it by using cross multiplication method.

(i)x – 3y – 3 = 0 ; 3x – 9y – 2 =0
(ii)2x + y = 5 ; 3x +2y =8
(iii)3x – 5y = 20 ; 6x – 10y =40
(iv)x – 3y – 7 = 0 ;3x – 3y – 15= 0

Question 2. (i) For which values of a and b does the following pair of linear equations have an infinite number of solutions?

2x +3y =7; (a – b) x +(a +b) y =3a +b –2

Question 3. Solve the following pair of linear equations by the substitution and cross-multiplication methods:

8x +5y =9 …(1)
3x +2y =4 …(2)

Quesiton 4. Form the pair of linear equations in the following problems and find their solutions (if they exist) by any algebraic method :

(ii) A fraction becomes 1 3 when 1 is subtracted from the numerator and it becomes 1 4 when 8 is added to its denominator. Find the fraction.

(iii) Yash scored 40 marks in a test, getting 3 marks for each right answer and losing 1 mark for each wrong answer. Had 4 marks been awarded for each correct answer and 2 marks been deducted for each incorrect answer, then Yash would have scored 50 marks. How many questions were there in the test?

(iv) Places A and B are 100 km apart on a highway. One car starts from A and another from B at the same time. If the cars travel in the same direction at different speeds, they meet in 5 hours. If they travel towards each other, they meet in 1 hour. What are the speeds of the two cars?

(v) The area of a rectangle gets reduced by 9 square units, if its length is reduced by 5 units and breadth is increased by 3 units. If we increase the length by 3 units and the breadth by 2 units, the area increases by 67 square units. Find the dimensions of the rectangle.

EXERCISE 3.6

Question 1. Solve the following pairs of equations by reducing them to a pair of linear equations:

Question 2. Formulate the following problems as a pair of equations, and hence find their solutions:

(i) Ritu can row downstream 20 km in 2 hours, and upstream 4 km in 2 hours. Find her speed of rowing in still water and the speed of the current.
(ii) 2 women and 5 men can together finish an embroidery work in 4 days, while 3 women and 6 men can finish it in 3 days. Find the time taken by 1 woman alone to finish the work, and also that taken by 1 man alone
(iii) Roohi travels 300 km to her home partly by train and partly by bus. She takes 4 hours if she travels 60 km by train and the remaining by bus. If she travels 100 km by train and the remaining by bus, she takes 10 minutes longer. Find the speed of the train and the bus separately.

EXERCISE 3.7

Question 1. The ages of two friends Ani and Biju differ by 3 years. Ani’s father Dharam is twice as old as Ani and Biju is twice as old as his sister Cathy. The ages of Cathy and Dharam differ by 30 years. Find the ages of Ani and Biju.

Question 2. One says, “Give me a hundred, friend! I shall then become twice as rich as you”. The other replies, “If you give me ten, I shall be six times as rich as you”. Tell me what is the amount of their (respective) capital? [From the Bijaganita of Bhaskara II] [Hint : x + 100 = 2(y – 100), y + 10 = 6(x – 10)

Question 3. A train covered a certain distance at a uniform speed. If the train would have been 10 km/h faster, it would have taken 2 hours less than the scheduled time. And, if the train were slower by 10 km/h; it would have taken 3 hours more than the scheduled time. Find the distance covered by the train.

Question 4. The students of a class are made to stand in rows. If 3 students are extra in a row, there would be 1 row less. If 3 students are less in a row, there would be 2 rows more. Find the number of students in the class.

Question 5. In a Δ ABC, ∠ C = 3 ∠ B = 2 (∠ A + ∠ B). Find the three angles.

Question 6. Draw the graphs of the equations 5x – y = 5 and 3x – y = 3. Determine the co-ordinates of the vertices of the triangle formed by these lines and the y axis.

Question 7. Solve the following pair of linear equations:

:: Chapter 4 Quadratic Equations ::

EXERCISE 4.1

Question 1. Check whether the following are quadratic equations :

(i) (x + 1)2 = 2(x – 3)
(ii) x2 – 2x = (–2) (3 – x)
(iii) (x – 2)(x + 1) = (x – 1)(x + 3)
(iv) (x – 3)(2x +1) = x(x + 5)
(v) (2x – 1)(x – 3) = (x + 5)(x – 1)
(vi) x2 + 3x + 1 = (x – 2)2
(vii) (x + 2)3 = 2x (x2 – 1)
(viii) x3 – 4x2 – x + 1 = (x – 2)3

Question 2. Represent the following situations in the form of quadratic equations :

(i) The area of a rectangular plot is 528 m2. The length of the plot (in metres) is one more than twice its breadth. We need to find the length and breadth of the plot.
(ii) The product of two consecutive positive integers is 306. We need to find the integers.
(iii) Rohan’s mother is 26 years older than him. The product of their ages (in years) 3 years from now will be 360. We would like to find Rohan’s present age.
(iv) A train travels a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, then it would have taken 3 hours more to cover the same distance. We need to find the speed of the train.

EXERCISE 4.2

Question 1. Find the roots of the following quadratic equations by factorisation:

(i) x2 – 3x – 10 = 0
(ii) 2x2 + x – 6 = 0
(iii) 2 x2 + 7 x + 5 2 = 0
(iv) 2x2 – x + 1 8 = 0
(v) 100 x2 – 20x + 1 = 0

Question 2. Solve the problems given in Example 1.

Question 3. Find two numbers whose sum is 27 and product is 182.

Question 4. Find two consecutive positive integers, sum of whose squares is 365.

Question 5. The altitude of a right triangle is 7 cm less than its base. If the hypotenuse is 13 cm, find the other two sides.

Question 6. A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was Rs 90, find the number of articles produced and the cost of each article.

EXERCISE 4.3

Question 1. Find the roots of the following quadratic equations, if they exist, by the method of completing the square:

(i) 2x2 – 7x + 3 = 0
(ii) 2x2 + x – 4 = 0
(iii) 4x2 + 4 3x + 3 = 0
(iv) 2x2 + x + 4 = 0

Question 2. Find the roots of the quadratic equations given in Q.1 above by applying the quadratic formula.

Question 3. The sum of the reciprocals of Rehman’s ages, (in years) 3 years ago and 5 years from now is 1.3 Find his present age.

Question 4. In a class test, the sum of Shefali’s marks in Mathematics and English is 30. Had she got 2 marks more in Mathematics and 3 marks less in English, the product of their marks would have been 210. Find her marks in the two subjects.

Question 5. The diagonal of a rectangular field is 60 metres more than the shorter side. If the longer side is 30 metres more than the shorter side, find the sides of the field.

Question 6. The difference of squares of two numbers is 180. The square of the smaller number is 8 times the larger number. Find the two numbers.

Question 7. A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.

Question 8. Two water taps together can fill a tank in 9 3 8 hours. The tap of larger diameter takes 10 hours less than the smaller one to fill the tank separately. Find the time in which each tap can separately fill the tank.

Question 9. An express train takes 1 hour less than a passenger train to travel 132 km between Mysore and Bangalore (without taking into consideration the time they stop at intermediate stations). If the average speed of the express train is 11km/h more than that of the passenger train, find the average speed of the two trains.

Question 10. Sum of the areas of two squares is 468 m2. If the difference of their perimeters is 24 m, find the sides of the two squares.

EXERCISE 4.4

Question 1. Find the nature of the roots of the following quadratic equations. If the real roots exist, find them:

(i) 2x2 – 3x + 5 = 0
(ii) 3x2 – 4 3 x + 4 = 0
(iii) 2x2 – 6x + 3 = 0

Question 2. Find the values of k for each of the following quadratic equations, so that they have two equal roots.

(i) 2x2 + kx + 3 = 0
(ii) kx (x – 2) + 6 = 0

Question 3. Is it possible to design a rectangular mango grove whose length is twice its breadth, and the area is 800 m2? If so, find its length and breadth.

Question 4. Is the following situation possible? If so, determine their present ages. The sum of the ages of two friends is 20 years. Four years ago, the product of their ages in years was 48.

Question 5. Is it possible to design a rectangular park of perimeter 80 m and area 400 m2? If so, find its length and breadth. 

:: Chapter 5 Arithmetic Progressions ::

EXERCISE 5.1

Question 1. In which of the following situations, does the list of numbers involved make an arithmetic progression, and why?

(i) The taxi fare after each km when the fare is Rs 15 for the first km and Rs 8 for each additional km.
(ii) The amount of air present in a cylinder when a vacuum pump removes 1 4 of the air remaining in the cylinder at a time.
(iii) The cost of digging a well after every metre of digging, when it costs Rs 150 for the first metre and rises by Rs 50 for each subsequent metre.
(iv) The amount of money in the account every year, when Rs 10000 is deposited at compound interest at 8 % per annum.]

EXERCISE 5.2

Question 1. Check whether – 150 is a term of the AP : 11, 8, 5, 2 . . .

Question 2. Find the 31st term of an AP whose 11th term is 38 and the 16th term is 73.

Question 3. An AP consists of 50 terms of which 3rd term is 12 and the last term is 106. Find the 29th term.

Question 4. If the 3rd and the 9th terms of an AP are 4 and – 8 respectively, which term of this AP is zero?

Question 5. The 17th term of an AP exceeds its 10th term by 7. Find the common difference.

Question 6. Which term of the AP : 3, 15, 27, 39, . . . will be 132 more than its 54th term?

Question 7. Two APs have the same common difference. The difference between their 100th terms is 100, what is the difference between their 1000th terms?

Question 8. How many three-digit numbers are divisible by 7?

Question 9. How many multiples of 4 lie between 10 and 250?

Question 10. For what value of n, are the nth terms of two APs: 63, 65, 67, . . . and 3, 10, 17, . . . equal? 16. Determine the AP whose third term is 16 and the 7th term exceeds the 5th term by 12.

EXERCISE 5.3

Question 1. Find the sum of the following APs:

(i) 2, 7, 12, . . ., to 10 terms.
(ii) –37, –33, –29, . . ., to 12 terms.
(iii) 0.6, 1.7, 2.8, . . ., to 100 terms.
(iv) 1 , 1 , 1 15 12 10 , . . ., to 11 terms.

Question 2. Find the sums given below :

(i) 7 + 10 1 2 + 14 + . . . + 84
(ii) 34 + 32 + 30 + . . . + 10
(iii) –5 + (–8) + (–11) + . . . + (–230) 3. In an AP:

(i) given a = 5, d = 3, an = 50, find n and Sn.
(ii) given a = 7, a13 = 35, find d and S13.
(iii) given a12 = 37, d = 3, find a and S12.
(iv) given a3 = 15, S10 = 125, find d and a10.
(v) given d = 5, S9 = 75, find a and a9. (vi) given a = 2, d = 8, Sn = 90, find n and an.
(vii) given a = 8, an = 62, Sn = 210, find n and d.
(viii) given an = 4, d = 2, Sn = –14, find n and a.
(ix) given a = 3, n = 8, S = 192, find d. (x) given l = 28, S = 144, and there are total 9 terms. Find a

Question 4. How many terms of the AP : 9, 17, 25, . . . must be taken to give a sum of 636?

Question 5. The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.

Question 6. The first and the last terms of an AP are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum?

Question 7. Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.

Question 8. Find the sum of first 51 terms of an AP whose second and third terms are 14 and 18 respectively.

Question 9. If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of first n terms.

Question 10. Show that a1, a2, . . ., an, . . . form an AP where an is defined as below :

(i) an = 3 + 4n
(ii) an = 9 – 5n Also find the sum of the first 15 terms in each case.

Question 11. If the sum of the first n terms of an AP is 4n – n2, what is the first term (that is S1)? What is the sum of first two terms? What is the second term? Similarly, find the 3rd, the 10th and the nth terms.

Question 12. Find the sum of the first 40 positive integers divisible by 6.

Question 13. Find the sum of the first 15 multiples of 8.

Question 14. Find the sum of the odd numbers between 0 and 50.

Question 15. A contract on construction job specifies a penalty for delay of completion beyond a certain date as follows: Rs 200 for the first day, Rs 250 for the second day, Rs 300 for the third day, etc., the penalty for each succeeding day being Rs 50 more than for the preceding day. How much money the contractor has to pay as penalty, if he has delayed the work by 30 days?

Question 16. A sum of Rs 700 is to be used to give seven cash prizes to students of a school for their overall academic performance. If each prize is Rs 20 less than its preceding prize, find the value of each of the prizes.

Question 17. In a school, students thought of planting trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be the same as the class, in which they are studying, e.g., a section of Class I will plant 1 tree, a section of Class II will plant 2 trees and so on till Class XII. There are three sections of each class. How many trees will be planted by the students?

Question 18. A spiral is made up of successive semicircles, with centres alternately at A and B, starting with centre at A, of radii 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, . . . as shown in Fig. 5.4. What is the total length of such a spiral made up of thirteen consecutive semicircles? (Take π = 22 7 ) 114 MATHEMATICS Fig. 5.4 [Hint : Length of successive semicircles is l1, l2, l3, l4, . . . with centres at A, B, A, B, . . ., respectively.]

Question 19. 200 logs are stacked in the following manner: 20 logs in the bottom row, 19 in the next row, 18 in the row next to it and so on (see Fig. 5.5). In how may rows are the 200 logs placed and how many logs are in the top row? Fig. 5.5

Question 20. In a potato race, a bucket is placed at the starting point, which is 5 m from the first potato, and the other potatoes are placed 3 m apart in a straight line. There are ten potatoes in the line (see Fig. 5.6). Fig. 5.6 A competitor starts from the bucket, picks up the nearest potato, runs back with it, drops it in the bucket, runs back to pick up the next potato, runs to the bucket to drop it in, and she continues in the same way until all the potatoes are in the bucket. What is the total distance the competitor has to run? [Hint : To pick up the first potato and the second potato, the total distance (in metres) run by a competitor is 2 × 5 + 2 × (5 + 3)]

EXERCISE 5.4

Question 1. Which term of the AP : 121, 117, 113, . . ., is its first negative term? [Hint : Find n for an < 0]

Question 2. The sum of the third and the seventh terms of an AP is 6 and their product is 8. Find the sum of first sixteen terms of the AP.

Question 3. A ladder has rungs 25 cm apart. (see Fig. 5.7). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and the bottom rungs are 2 1 2 m apart, what is the length of the wood required for the rungs? [Hint : Number of rungs = 250 25 ]

Question 4. The houses of a row are numbered consecutively from 1 to 49. Show that there is a value of x such that the sum of the numbers of the houses preceding the house numbered x is equal to the sum of the numbers of the houses following it. Find this value of x. [Hint : Sx – 1 = S49 – Sx]

Question 5. A small terrace at a football ground comprises of 15 steps each of which is 50 m long and built of solid concrete. Each step has a rise of 1 4 m and a tread of 1 2 m. (see Fig. 5.8). Calculate the total volume of concrete required to build the terrace. [Hint : Volume of concrete required to build the first step = 1 1 50 m3 4 2 × × ]

:: Chapter 6 Triangles ::

Theorems

Theorem 6.1: If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, the other two sides are divided in the same ratio.

Theorem 6.8 : In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.

:: Chapter 7 Coordinate Geometry ::

EXERCISE 7.1

Question 1. Find the distance between the following pairs of points :

(i) (2, 3), (4, 1)
(ii) (– 5, 7), (– 1, 3)
(iii) (a, b), (– a, – b) 

Question 2. Find the distance between the points (0, 0) and (36, 15). Can you now find the distance between the two towns A and B discussed in Section 7.2.

Question 3. Determine if the points (1, 5), (2, 3) and (– 2, – 11) are collinear.

Question 4. Check whether (5, – 2), (6, 4) and (7, – 2) are the vertices of an isosceles triangle.

Question 5. In a classroom, 4 friends are seated at the points A, B, C and D as shown in Fig. 7.8. Champa and Chameli walk into the class and after observing for a few minutes Champa asks Chameli, “Don’t you think ABCD is a square?” Chameli disagrees. Using distance formula, find which of them is correct.

Question 6. Name the type of quadrilateral formed, if any, by the following points, and give reasons for your answer:

(i) (– 1, – 2), (1, 0), (– 1, 2), (– 3, 0)
(ii) (–3, 5), (3, 1), (0, 3), (–1, – 4)
(iii) (4, 5), (7, 6), (4, 3), (1, 2)

Question 7. Find the point on the x-axis which is equidistant from (2, –5) and (–2, 9).

Question 8. Find the values of y for which the distance between the points P(2, – 3) and Q(10, y) is 10 units

Question 9. If Q(0, 1) is equidistant from P(5, –3) and R(x, 6), find the values of x. Also find the distances QR and PR.

Question 10. Find a relation between x and y such that the point (x, y) is equidistant from the point (3, 6) and (– 3, 4).

EXERCISE 7.2

Question 1. Find the coordinates of the point which divides the join of (–1, 7) and (4, –3) in the ratio 2 : 3.

Question 2. Find the coordinates of the points of trisection of the line segment joining (4, –1) and (–2, –3).

Question 3. To conduct Sports Day activities, in your rectangular shaped school ground ABCD, lines have been drawn with chalk powder at a distance of 1m each. 100 flower pots have been placed at a distance of 1m from each other along AD, as shown in Fig. 7.12. Niharika runs 1 4 th the distance AD on the 2nd line and posts a green flag. Preet runs 1 5 th the distance AD on the eighth line and posts a red flag. What is the distance between both the flags? If Rashmi has to post a blue flag exactly halfway between the line segment joining the two flags, where should she post her flag?

Question 4. Find the ratio in which the line segment joining the points (– 3, 10) and (6, – 8) is divided by (– 1, 6).

Question 5. Find the ratio in which the line segment joining A(1, – 5) and B(– 4, 5) is divided by the x-axis. Also find the coordinates of the point of division.

Question 6. If (1, 2), (4, y), (x, 6) and (3, 5) are the vertices of a parallelogram taken in order, find x and y.

Question 7. Find the coordinates of a point A, where AB is the diameter of a circle whose centre is (2, – 3) and B is (1, 4).

Question 8. If A and B are (– 2, – 2) and (2, – 4), respectively, find the coordinates of P such that AP = 3 AB 7 and P lies on the line segment AB.

Question 9. Find the coordinates of the points which divide the line segment joining A(– 2, 2) and B(2, 8) into four equal parts.

Question 10. Find the area of a rhombus if its vertices are (3, 0), (4, 5), (– 1, 4) and (– 2, – 1) taken in order. [Hint : Area of a rhombus = 1 2 (product of its diagonals)]

EXERCISE 7.3

Question 1. Find the area of the triangle whose vertices are :

(i) (2, 3), (–1, 0), (2, – 4)
(ii) (–5, –1), (3, –5), (5, 2)

Question 2. In each of the following find the value of ‘k’, for which the points are collinear.

(i) (7, –2), (5, 1), (3, k)
(ii) (8, 1), (k, – 4), (2, –5)

Question 3. Find the area of the triangle formed by joining the mid-points of the sides of the triangle whose vertices are (0, –1), (2, 1) and (0, 3). Find the ratio of this area to the area of the given triangle.

Question 4. Find the area of the quadrilateral whose vertices, taken in order, are (– 4, – 2), (– 3, – 5), (3, – 2) and (2, 3).

Question 5. You have studied in Class IX, (Chapter 9, Example 3), that a median of a triangle divides it into two triangles of equal areas. Verify this result for Δ ABC whose vertices are A(4, – 6), B(3, –2) and C(5, 2).

EXERCISE 7.4

Question 1. Determine the ratio in which the line 2x + y – 4 = 0 divides the line segment joining the points A(2, – 2) and B(3, 7).

Question 2. Find a relation between x and y if the points (x, y), (1, 2) and (7, 0) are collinear.

Question 3. Find the centre of a circle passing through the points (6, – 6), (3, – 7) and (3, 3).

Question 4. The two opposite vertices of a square are (–1, 2) and (3, 2). Find the coordinates of the other two vertices.

Question 5. The Class X students of a secondary school in Krishinagar have been allotted a rectangular plot of land for their gardening activity. Sapling of Gulmohar are planted on the boundary at a distance of 1m from each other. There is a triangular grassy lawn in the plot as shown in the Fig. 7.14. The students are to sow seeds of flowering plants on the remaining area of the plot.

(i) Taking A as origin, find the coordinates of the vertices of the triangle.
(ii) What will be the coordinates of the vertices of Δ PQR if C is the origin? Also calculate the areas of the triangles in these cases. What do you observe?

Question 6. The vertices of a Δ ABC are A(4, 6), B(1, 5) and C(7, 2). A line is drawn to intersect sides AB and AC at D and E respectively, such that AD AE 1 AB AC 4 = Calculate the area of the Δ ADE and compare it with the area of Δ ABC. (Recall Theorem 6.2 and Theorem 6.6).

Question 7. Let A (4, 2), B(6, 5) and C(1, 4) be the vertices of Δ ABC.

(i) The median from A meets BC at D. Find the coordinates of the point D.
(ii) Find the coordinates of the point P on AD such that AP : PD = 2 : 1
(iii) Find the coordinates of points Q and R on medians BE and CF respectively such that BQ : QE = 2 : 1 and CR : RF = 2 : 1.
(iv) What do yo observe?

[Note : The point which is common to all the three medians is called the centroid and this point divides each median in the ratio 2 : 1.]

:: Chapter 8 Introduction To Trigonometry ::

EXERCISE 8.1

Question 1. In Δ ABC, right-angled at B, AB = 24 cm, BC = 7 cm. Determine :

(i) sin A, cos A
(ii) sin C, cos C ]

Question 2. In Fig. 8.13, find tan P – cot R.

Question 3. If sin A = 3 , 4 calculate cos A and tan A.

Question 4. Given 15 cot A = 8, find sin A and sec A.

Question 5. Given sec θ = 13 , 12 calculate all other trigonometric ratios.

Question 6. If ∠ A and ∠ B are acute angles such that cos A = cos B, then show that ∠ A = ∠ B.

Question 7. If cot θ = 7 , 8 evaluate :

(i) (1 sin ) (1 sin ) , (1 cos ) (1 cos ) + θ − θ + θ − θ
(ii) cot2 θ

Question 8. If 3 cot A = 4, check whether 2 2 1 tan A 1 + tan A − = cos2 A – sin2A or not.

Question 9. In triangle ABC, right-angled at B, if tan A = 1 , 3 find the value of: (i) sin A cos C + cos A sin C (ii) cos A cos C – sin A sin C

Question 10. In Δ PQR, right-angled at Q, PR + QR = 25 cm and PQ = 5 cm. Determine the values of sin P, cos P and tan P.

Question 11. State whether the following are true or false. Justify your answer.

(i) The value of tan A is always less than 1.
(ii) sec A = 12 5 for some value of angle A.
(iii) cos A is the abbreviation used for the cosecant of angle A.
(iv) cot A is the product of cot and A.
(v) sin θ = 4 3 for some angle θ.

EXERCISE 8.2

Question 1. Evaluate the following :

(i) sin 60° cos 30° + sin 30° cos 60°
(ii) 2 tan2 45° + cos2 30° – sin2 60° 

Question 3. If tan (A + B) = 3 and tan (A – B) = 1 3 ; 0° < A + B ≤ 90°; A > B, find A and B.

Question 4. State whether the following are true or false. Justify your answer.

(i) sin (A + B) = sin A + sin B.
(ii) The value of sin θ increases as θ increases.
(iii) The value of cos θ increases as θ increases.
(iv) sin θ = cos θ for all values of θ.
(v) cot A is not defined for A = 0°.

EXERCISE 8.3

Question 1. Evaluate :

(i) sin 18 cos 72 ° °
(ii) tan 26 cot 64 ° °
(iii) cos 48° – sin 42°
(iv) cosec 31° – sec 59°

Question 2. Show that :

(i) tan 48° tan 23° tan 42° tan 67° = 1
(ii) cos 38° cos 52° – sin 38° sin 52° = 0

Question 3. If tan 2A = cot (A – 18°), where 2A is an acute angle, find the value of A.

Question 4. If tan A = cot B, prove that A + B = 90°. 5. If sec 4A = cosec (A – 20°), where 4A is an acute angle, find the value of A.

EXERCISE 8.4

Question 1. Express the trigonometric ratios sin A, sec A and tan A in terms of cot A.

Question 2. Write all the other trigonometric ratios of ∠ A in terms of sec A.

Question 3. Evaluate :

(i) 2 2 2 2 sin 63 sin 27 cos 17 cos 73 ° + ° ° + °
(ii) sin 25° cos 65° + cos 25° sin 65°

Question 4. Choose the correct option. Justify your choice.

(i) 9 sec2 A – 9 tan2 A =

(A) 1
(B) 9
(C) 8
(D) 0

(ii) (1 + tan θ + sec θ) (1 + cot θ – cosec θ) =

(A) 0
(B) 1
(C) 2
(D) –1

(iii) (sec A + tan A) (1 – sin A) =

(A) sec A
(B) sin A
(C) cosec A
(D) cos A

(iv) 2 2 1 tan A 1 + cot A + =

(A) sec2 A
(B) –1
(C) cot2 A
(D) tan2 A

Question 5. Prove the following identities, where the angles involved are acute angles for which the expressions are defined.

(i) (cosec θ – cot θ)2 = 1 cos 1 cos − θ + θ
(ii) cos A 1 sin A 2 sec A
(iii) tan cot 1 sec cosec 1 cot 1 tan θ θ + = + θ θ − θ − θ [Hint : Write the expression in terms of sin θ and cos θ]
(iv) 1 sec A sin2 A sec A 1 – cos A + = [Hint : Simplify LHS and RHS separately]
(v) cos A – sin A + 1 cosec A + cot A, cos A + sin A – 1 = using the identity cosec2 A = 1 + cot2 A.
(vi) 1 sinA sec A + tan A 1 – sin A + =
(vii) 3 3 sin 2 sin tan 2 cos cos θ − θ = θ θ − θ
(viii) (sin A + cosec A)2 + (cos A + sec A)2 = 7 + tan2 A + cot2 A
(ix) (cosec A – sin A)(sec A – cos A) 1 tanA + cot A = [Hint : Simplify LHS and RHS separately]
(x) 2 2 2 1 tan A 1 tanA 1 + cot A 1 – cot A = tan2 A

:: Chapter 9 Some Applications of Trigonometry ::

EXERCISE 9.1

Question 1. A circus artist is climbing a 20 m long rope, which is tightly stretched and tied from the top of a vertical pole to the ground. Find the height of the pole, if the angle made by the rope with the ground level is 30°

Question 2. A tree breaks due to storm and the broken part bends so that the top of the tree touches the ground making an angle 30° with it. The distance between the foot of the tree to the point where the top touches the ground is 8 m. Find the height of the tree.

Question 3. A contractor plans to install two slides for the children to play in a park. For the children below the age of 5 years, she prefers to have a slide whose top is at a height of 1.5 m, and is inclined at an angle of 30° to the ground, whereas for elder children, she wants to have a steep slide at a height of 3m, and inclined at an angle of 60° to the ground. What should be the length of the slide in each case?

Question 4. The angle of elevation of the top of a tower from a point on the ground, which is 30 m away from the foot of the tower, is 30°. Find the height of the tower.

Question 5. A kite is flying at a height of 60 m above the ground. The string attached to the kite is temporarily tied to a point on the ground. The inclination of the string with the ground is 60°. Find the length of the string, assuming that there is no slack in the string.

Question 6. A 1.5 m tall boy is standing at some distance from a 30 m tall building. The angle of elevation from his eyes to the top of the building increases from 30° to 60° as he walks towards the building. Find the distance he walked towards the building.

Question 7. From a point on the ground, the angles of elevation of the bottom and the top of a transmission tower fixed at the top of a 20 m high building are 45° and 60° respectively. Find the height of the tower.

Question 8. A statue, 1.6 m tall, stands on the top of a pedestal. From a point on the ground, the angle of elevation of the top of the statue is 60° and from the same point the angle of elevation of the top of the pedestal is 45°. Find the height of the pedestal.

Question 9. The angle of elevation of the top of a building from the foot of the tower is 30° and the angle of elevation of the top of the tower from the foot of the building is 60°. If the tower is 50 m high, find the height of the building.

Question 10. Two poles of equal heights are standing opposite each other on either side of the road, which is 80 m wide. From a point between them on the road, the angles of elevation of the top of the poles are 60° and 30°, respectively. Find the height of the poles and the distances of the point from the poles.

Question 11. A TV tower stands vertically on a bank of a canal. From a point on the other bank directly opposite the tower, the angle of elevation of the top of the tower is 60°. From another point 20 m away from this point on the line joing this point to the foot of the tower, the angle of elevation of the top of the tower is 30° (see Fig. 9.12). Find the height of the tower and the width of the canal.

Question 12. From the top of a 7 m high building, the angle of elevation of the top of a cable tower is 60° and the angle of depression of its foot is 45°. Determine the height of the tower.

Question 13. As observed from the top of a 75 m high lighthouse from the sea-level, the angles of depression of two ships are 30° and 45°. If one ship is exactly behind the other on the same side of the lighthouse, find the distance between the two ships.

Question 14. A 1.2 m tall girl spots a balloon moving with the wind in a horizontal line at a height of 88.2 m from the ground. The angle of elevation of the balloon from the eyes of the girl at any instant is 60°. After some time, the angle of elevation reduces to 30° (see Fig. 9.13). Find the distance travelled by the balloon during the interval.

Question 15. A straight highway leads to the foot of a tower. A man standing at the top of the tower observes a car at an angle of depression of 30°, which is approaching the foot of the tower with a uniform speed. Six seconds later, the angle of depression of the car is found to be 60°. Find the time taken by the car to reach the foot of the tower from this point.

Question 16. The angles of elevation of the top of a tower from two points at a distance of 4 m and 9 m from the base of the tower and in the same straight line with it are complementary. Prove that the height of the tower is 6 m.

:: Chapter 10 Circles ::

EXERCISE 10.1

Question 1. How many tangents can a circle have? 2. Fill in the blanks :

(i) A tangent to a circle intersects it in point (s).
(ii) A line intersecting a circle in two points is called a .
(iii) A circle can have parallel tangents at the most.
(iv) The common point of a tangent to a circle and the circle is called .

Question 2. A tangent PQ at a point P of a circle of radius 5 cm meets a line through the centre O at a point Q so that OQ = 12 cm. Length PQ is :

(A) 12 cm
(B) 13 cm
(C) 8.5 cm
(D) 119 cm.

Question 3. Draw a circle and two lines parallel to a given line such that one is a tangent and the other, a secant to the circle.

EXERCISE 10.2

Question 1. From a point Q, the length of the tangent to a circle is 24 cm and the distance of Q from the centre is 25 cm. The radius of the circle is

(A) 7 cm
(B) 12 cm
(C) 15 cm
(D) 24.5 cm

Question 2. In Fig. 10.11, if TP and TQ are the two tangents to a circle with centre O so that ∠ POQ = 110°, then ∠ PTQ is equal to

(A) 60°
(B) 70°
(C) 80°
(D) 90°

Question 3. If tangents PA and PB from a point P to a circle with centre O are inclined to each other at angle of 80°, then ∠ POA is equal to

(A) 50°
(B) 60°
(C) 70°
(D) 80°

Question 4. Prove that the perpendicular at the point of contact to the tangent to a circle passes through the centre.

Question 5. The length of a tangent from a point A at distance 5 cm from the centre of the circle is 4 cm. Find the radius of the circle.

Question 6. Two concentric circles are of radii 5 cm and 3 cm. Find the length of the chord of the larger circle which touches the smaller circle.

Question 7. A quadrilateral ABCD is drawn to circumscribe a circle (see Fig. 10.12). Prove that AB + CD = AD + BC Fig. 10.12 Fig. 10.13

Question 8. In Fig. 10.13, XY and X′Y′ are two parallel tangents to a circle with centre O and another tangent AB with point of contact C intersecting XY at A and X′Y at B. Prove that ∠ AOB = 90°.

Question 9. Prove that the angle between the two tangents drawn from an external point to a circle is supplementary to the angle subtended by the line-segment joining the points of contact at the centre.

Question 10. Prove that the parallelogram circumscribing a circle is a rhombus.

Question 11. A triangle ABC is drawn to circumscribe a circle of radius 4 cm such that the segments BD and DC into which BC is divided by the point of contact D are of lengths 8 cm and 6 cm respectively (see Fig. 10.14). Find the sides AB and AC.

Question 12. Prove that opposite sides of a quadrilateral circumscribing a circle subtend supplementary angles at the centre of the circle.

:: Chapter 11 Constructions ::

EXERCISE 11.1

In each of the following, give the justification of the construction also:

Question 1. Draw a line segment of length 7.6 cm and divide it in the ratio 5 : 8. Measure the two parts.

Question 2. Construct a triangle of sides 4 cm, 5 cm and 6 cm and then a triangle similar to it whose sides are 2 3 of the corresponding sides of the first triangle.

Question 3. Construct a triangle with sides 5 cm, 6 cm and 7 cm and then another triangle whose sides are 7 5 of the corresponding sides of the first triangle.

Question 4. Construct an isosceles triangle whose base is 8 cm and altitude 4 cm and then another triangle whose sides are 1 1 2 times the corresponding sides of the isosceles triangle.

Question 5. Draw a triangle ABC with side BC = 6 cm, AB = 5 cm and ∠ ABC = 60°. Then construct a triangle whose sides are 3 4 of the corresponding sides of the triangle ABC.

Question 6. Draw a triangle ABC with side BC = 7 cm, ∠ B = 45°, ∠ A = 105°. Then, construct a triangle whose sides are 4 3 times the corresponding sides of Δ ABC.

Question 7. Draw a right triangle in which the sides (other than hypotenuse) are of lengths 4 cm and 3 cm. Then construct another triangle whose sides are 5 3 times the corresponding sides of the given triangle.

EXERCISE 11.2

In each of the following, give also the justification of the construction:

Question 1. Draw a circle of radius 6 cm. From a point 10 cm away from its centre, construct the pair of tangents to the circle and measure their lengths.

Question 2. Construct a tangent to a circle of radius 4 cm from a point on the concentric circle of radius 6 cm and measure its length. Also verify the measurement by actual calculation.

Question 3. Draw a circle of radius 3 cm. Take two points P and Q on one of its extended diameter each at a distance of 7 cm from its centre. Draw tangents to the circle from these two points P and Q.

Question 4. Draw a pair of tangents to a circle of radius 5 cm which are inclined to each other at an angle of 60°.

Question 5. Draw a line segment AB of length 8 cm. Taking A as centre, draw a circle of radius 4 cm and taking B as centre, draw another circle of radius 3 cm. Construct tangents to each circle from the centre of the other circle.

:: Chapter 12 Areas Related To Circles ::

EXERCISE 12.1

1 Unless stated otherwise, use π = 22/7 .

Question 1. The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles.

Question 2. The radii of two circles are 8 cm and 6 cm respectively. Find the radius of the circle having area equal to the sum of the areas of the two circles.

Question 3. Fig. 12.3 depicts an archery target marked with its five scoring areas from the centre outwards as Gold, Red, Blue, Black and White. The diameter of the region representing Gold score is 21 cm and each of the other bands is 10.5 cm wide. Find the area of each of the five scoring regions.

Question 4. The wheels of a car are of diameter 80 cm each. How many complete revolutions does each wheel make in 10 minutes when the car is travelling at a speed of 66 km per hour?

Question 5. Tick the correct answer in the following and justify your choice : If the perimeter and the area of a circle are numerically equal, then the radius of the circle is

(A) 2 units
(B) π units
(C) 4 units
(D) 7 units

EXERCISE 12.2

Unless stated otherwise, use π = 22/7 .

Question 1. Find the area of a sector of a circle with radius 6 cm if angle of the sector is 60° .

Question 2. Find the area of a quadrant of a circle whose circumference is 22 cm.

Question 3. The length of the minute hand of a clock is 14 cm. Find the area swept by the minute hand in 5 minutes.

Question 4. A chord of a circle of radius 10 cm subtends a right angle at the centre. Find the area of the corresponding :

(i) minor segment
(ii) major sector. (Use π = 3.14)

Question 5. In a circle of radius 21 cm, an arc subtends an angle of 60° at the centre. Find:

(i) the length of the arc
(ii) area of the sector formed by the arc
(iii) area of the segment formed by the corresponding chord

Question 6. A chord of a circle of radius 15 cm subtends an angle of 60° at the centre. Find the areas of the corresponding minor and major segments of the circle. (Use π = 3.14 and 3 = 1.73)

Question 7. A chord of a circle of radius 12 cm subtends an angle of 120° at the centre. Find the area of the corresponding segment of the circle. (Use π = 3.14 and 3 = 1.73)

Question 8. A horse is tied to a peg at one corner of a square shaped grass field of side 15 m by means of a 5 m long rope (see Fig. 12.11). Find

(i) the area of that part of the field in which the horse can graze.
(ii) the increase in the grazing area if the rope were 10 m long instead of 5 m. (Use π = 3.14)

Question 9. A brooch is made with silver wire in the form of a circle with diameter 35 mm. The wire is also used in making 5 diameters which divide the circle into 10 equal sectors as shown in Fig. 12.12. Find :

(i) the total length of the silver wire required.
(ii) the area of each sector of the brooch.

Question 10. An umbrella has 8 ribs which are equally spaced (see Fig. 12.13). Assuming umbrella to be a flat circle of radius 45 cm, find the area between the two consecutive ribs of the umbrella.

Question 11. A car has two wipers which do not overlap. Each wiper has a blade of length 25 cm sweeping through an angle of 115°. Find the total area cleaned at each sweep of the blades.

Question 12. To warn ships for underwater rocks, a lighthouse spreads a red coloured light over a sector of angle 80° to a distance of 16.5 km. Find the area of the sea over which the ships are warned. (Use π = 3.14)

Question 13. A round table cover has six equal designs as shown in Fig. 12.14. If the radius of the cover is 28 cm, find the cost of making the designs at the rate of Rs 0.35 per cm2. (Use 3 = 1.7)

Question 14. Tick the correct answer in the following : Area of a sector of angle p (in degrees) of a circle with radius R is

(A) 2 R 180 p ×
(B) R2 180 p × π
(C) 2 R 360 p × π
(D) 2 R2 720 p ×

EXERCISE 12.3

Unless stated otherwise, use π = 22/ 7

Question 1. Find the area of the shaded region in Fig. 12.19, if PQ = 24 cm, PR = 7 cm and O is the centre of the circle.

Question 2. Find the area of the shaded region in Fig. 12.20, if radii of the two concentric circles with centre O are 7 cm and 14 cm respectively and ∠ AOC = 40°.

Question 3. Find the area of the shaded region in Fig. 12.21, if ABCD is a square of side 14 cm and APD and BPC are semicircles.

Question 4. Find the area of the shaded region in Fig. 12.22, where a circular arc of radius 6 cm has been drawn with vertex O of an equilateral triangle OAB of side 12 cm as centre.

Question 5. From each corner of a square of side 4 cm a quadrant of a circle of radius 1 cm is cut and also a circle of diameter 2 cm is cut as shown in Fig. 12.23. Find the area of the remaining portion of the square.

Question 6. In a circular table cover of radius 32 cm, a design is formed leaving an equilateral triangle ABC in the middle as shown in Fig. 12.24. Find the area of the design (shaded region).

Question 7. In Fig. 12.25, ABCD is a square of side 14 cm. With centres A, B, C and D, four circles are drawn such that each circle touch externally two of the remaining three circles. Find the area of the shaded region

Question 8. Fig. 12.26 depicts a racing track whose left and right ends are semicircular. The distance between the two inner parallel line segments is 60 m and they are each 106 m long. If the track is 10 m wide, find :

(i) the distance around the track along its inner edge
(ii) the area of the track.

Question 9. In Fig. 12.27, AB and CD are two diameters of a circle (with centre O) perpendicular to each other and OD is the diameter of the smaller circle. If OA = 7 cm, find the area of the shaded region.

Question 10. The area of an equilateral triangle ABC is 17320.5 cm2. With each vertex of the triangle as centre, a circle is drawn with radius equal to half the length of the side of the triangle (see Fig. 12.28). Find the area of the shaded region. (Use π = 3.14 and 3 = 1.73205)

Question 11. On a square handkerchief, nine circular designs each of radius 7 cm are made (see Fig. 12.29). Find the area of the remaining portion of the handkerchief.

Question 12. In Fig. 12.30, OACB is a quadrant of a circle with centre O and radius 3.5 cm. If OD = 2 cm, find the area of the (i) quadrant OACB, (ii) shaded region.

Question 13. In Fig. 12.31, a square OABC is inscribed in a quadrant OPBQ. If OA = 20 cm, find the area of the shaded region. (Use π = 3.14)

Question 14. AB and CD are respectively arcs of two concentric circles of radii 21 cm and 7 cm and centre O (see Fig. 12.32). If ∠ AOB = 30°, find the area of the shaded region.

Question 15. In Fig. 12.33, ABC is a quadrant of a circle of radius 14 cm and a semicircle is drawn with BC as diameter. Find the area of the shaded region.

Question 16. Calculate the area of the designed region in Fig. 12.34 common between the two quadrants of circles of radius 8 cm each

:: Chapter 13 Surface Areas and Volumes ::

EXERCISE 13.1

Unless stated otherwise, take π = 22 7

Question 1. 2 cubes each of volume 64 cm3 are joined end to end. Find the surface area of the resulting cuboid.

Question 2. A vessel is in the form of a hollow hemisphere mounted by a hollow cylinder. The diameter of the hemisphere is 14 cm and the total height of the vessel is 13 cm. Find the inner surface area of the vessel.

Question 3. A toy is in the form of a cone of radius 3.5 cm mounted on a hemisphere of same radius. The total height of the toy is 15.5 cm. Find the total surface area of the toy.

Question 4. A cubical block of side 7 cm is surmounted by a hemisphere. What is the greatest diameter the hemisphere can have? Find the surface area of the solid.

Question 5. A hemispherical depression is cut out from one face of a cubical wooden block such that the diameter l of the hemisphere is equal to the edge of the cube. Determine the surface area of the remaining solid.

Question 6. A medicine capsule is in the shape of a cylinder with two hemispheres stuck to each of its ends (see Fig. 13.10). The length of the entire capsule is 14 mm and the diameter of the capsule is 5 mm. Find its surface area.

Question 7. A tent is in the shape of a cylinder surmounted by a conical top. If the height and diameter of the cylindrical part are 2.1 m and 4 m respectively, and the slant height of the top is 2.8 m, find the area of the canvas used for making the tent. Also, find the cost of the canvas of the tent at the rate of Rs 500 per m2. (Note that the base of the tent will not be covered with canvas.)

Question 8. From a solid cylinder whose height is 2.4 cm and diameter 1.4 cm, a conical cavity of the same height and same diameter is hollowed out. Find the total surface area of the remaining solid to the nearest cm2.

Question 9. A wooden article was made by scooping out a hemisphere from each end of a solid cylinder, as shown in Fig. 13.11. If the height of the cylinder is 10 cm, and its base is of radius 3.5 cm, find the total surface area of the article.

EXERCISE 13.2

Unless stated otherwise, take π = 22 /7 .

Question 1. A solid is in the shape of a cone standing on a hemisphere with both their radii being equal to 1 cm and the height of the cone is equal to its radius. Find the volume of the solid in terms of π.

Question 2. Rachel, an engineering student, was asked to make a model shaped like a cylinder with two cones attached at its two ends by using a thin aluminium sheet. The diameter of the model is 3 cm and its length is 12 cm. If each cone has a height of 2 cm, find the volume of air contained in the model that Rachel made. (Assume the outer and inner dimensions of the model to be nearly the same.)

Question 3. A gulab jamun, contains sugar syrup up to about 30% of its volume. Find approximately how much syrup would be found in 45 gulab jamuns, each shaped like a cylinder with two hemispherical ends with length 5 cm and diameter 2.8 cm (see Fig. 13.15).

Question 4. A pen stand made of wood is in the shape of a cuboid with four conical depressions to hold pens. The dimensions of the cuboid are 15 cm by 10 cm by 3.5 cm. The radius of each of the depressions is 0.5 cm and the depth is 1.4 cm. Find the volume of wood in the entire stand (see Fig. 13.16).

Question 5. A vessel is in the form of an inverted cone. Its height is 8 cm and the radius of its top, which is open, is 5 cm. It is filled with water up to the brim. When lead shots, each of which is a sphere of radius 0.5 cm are dropped into the vessel, one-fourth of the water flows out. Find the number of lead shots dropped in the vessel.

Question 6. A solid iron pole consists of a cylinder of height 220 cm and base diameter 24 cm, which is surmounted by another cylinder of height 60 cm and radius 8 cm. Find the mass of the pole, given that 1 cm3 of iron has approximately 8g mass. (Use π = 3.14)

Question 7. A solid consisting of a right circular cone of height 120 cm and radius 60 cm standing on a hemisphere of radius 60 cm is placed upright in a right circular cylinder full of water such that it touches the bottom. Find the volume of water left in the cylinder, if the radius of the cylinder is 60 cm and its height is 180 cm.

Question 8. A spherical glass vessel has a cylindrical neck 8 cm long, 2 cm in diameter; the diameter of the spherical part is 8.5 cm. By measuring the amount of water it holds, a child finds its volume to be 345 cm3. Check whether she is correct, taking the above as the inside measurements, and π = 3.14

EXERCISE 13.3

Take π = 22 7 , unless stated otherwise.

Question 1. A metallic sphere of radius 4.2 cm is melted and recast into the shape of a cylinder of radius 6 cm. Find the height of the cylinder.

Question 2. Metallic spheres of radii 6 cm, 8 cm and 10 cm, respectively, are melted to form a single solid sphere. Find the radius of the resulting sphere.

Question 3. A 20 m deep well with diameter 7 m is dug and the earth from digging is evenly spread out to form a platform 22 m by 14 m. Find the height of the platform.

Question 4. A well of diameter 3 m is dug 14 m deep. The earth taken out of it has been spread evenly all around it in the shape of a circular ring of width 4 m to form an embankment. Find the height of the embankment.

Question 5. A container shaped like a right circular cylinder having diameter 12 cm and height 15 cm is full of ice cream. The ice cream is to be filled into cones of height 12 cm and diameter 6 cm, having a hemispherical shape on the top. Find the number of such cones which can be filled with ice cream.

Question 6. How many silver coins, 1.75 cm in diameter and of thickness 2 mm, must be melted to form a cuboid of dimensions 5.5 cm × 10 cm × 3.5 cm?

Question 7. A cylindrical bucket, 32 cm high and with radius of base 18 cm, is filled with sand. This bucket is emptied on the ground and a conical heap of sand is formed. If the height of the conical heap is 24 cm, find the radius and slant height of the heap.

Question 8. Water in a canal, 6 m wide and 1.5 m deep, is flowing with a speed of 10 km/h. How much area will it irrigate in 30 minutes, if 8 cm of standing water is needed?

Question 9. A farmer connects a pipe of internal diameter 20 cm from a canal into a cylindrical tank in her field, which is 10 m in diameter and 2 m deep. If water flows through the pipe at the rate of 3 km/h, in how much time will the tank be filled?

EXERCISE 13.4

Use π = 22/7 unless stated otherwise.

Question 1. A drinking glass is in the shape of a frustum of a cone of height 14 cm. The diameters of its two circular ends are 4 cm and 2 cm. Find the capacity of the glass.

Question 2. The slant height of a frustum of a cone is 4 cm and the perimeters (circumference) of its circular ends are 18 cm and 6 cm. Find the curved surface area of the frustum.

Question 3. A fez, the cap used by the Turks, is shaped like the frustum of a cone (see Fig. 13.24). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material used for making it.

Question 4. A container, opened from the top and made up of a metal sheet, is in the form of a frustum of a cone of height 16 cm with radii of its lower and upper ends as 8 cm and 20 cm, respectively. Find the cost of the milk which can completely fill the container, at the rate of Rs 20 per litre. Also find the cost of metal sheet used to make the container, if it costs Rs 8 per 100 cm2. (Take π = 3.14)

Question 5. A metallic right circular cone 20 cm high and whose vertical angle is 60° is cut into two parts at the middle of its height by a plane parallel to its base. If the frustum so obtained be drawn into a wire of diameter 1 cm, 16 find the length of the wire.

EXERCISE 13.5

Question 1. A copper wire, 3 mm in diameter, is wound about a cylinder whose length is 12 cm, and diameter 10 cm, so as to cover the curved surface of the cylinder. Find the length and mass of the wire, assuming the density of copper to be 8.88 g per cm3.

Question 2. A right triangle, whose sides are 3 cm and 4 cm (other than hypotenuse) is made to revolve about its hypotenuse. Find the volume and surface area of the double cone so formed. (Choose value of π as found appropriate.)

Question 3. A cistern, internally measuring 150 cm × 120 cm × 110 cm, has 129600 cm3 of water in it. Porous bricks are placed in the water until the cistern is full to the brim. Each brick absorbs one-seventeenth of its own volume of water. How many bricks can be put in without overflowing the water, each brick being 22.5 cm × 7.5 cm × 6.5 cm?

Question 4. In one fortnight of a given month, there was a rainfall of 10 cm in a river valley. If the area of the valley is 97280 km2, show that the total rainfall was approximately equivalent to the addition to the normal water of three rivers each 1072 km long, 75 m wide and 3 m deep.

Question 5. An oil funnel made of tin sheet consists of a 10 cm long cylindrical portion attached to a frustum of a cone. If the total height is 22 cm, diameter of the cylindrical portion is 8 cm and the diameter of the top of the funnel is 18 cm, find the area of the tin sheet required to make the funnel (see Fig. 13.25).

Question 6. Derive the formula for the curved surface area and total surface area of the frustum of a cone, given to you in Section 13.5, using the symbols as explained.

Question 7. Derive the formula for the volume of the frustum of a cone, given to you in Section 13.5, using the symbols as explained.

:: Chapter 14 Statistics ::

EXERCISE 14.1

Question 1. A survey was conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in 20 houses in a locality. Find the mean number of plants per house.Which method did you use for finding the mean, and why?

Question 2. Consider the following distribution of daily wages of 50 workers of a factory Find the mean daily wages of the workers of the factory by using an appropriate method.

Question 3. The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs 18. Find the missing frequency f.

Question 4. Thirty women were examined in a hospital by a doctor and the number of heart beats per minute were recorded and summarised as follows. Find the mean heart beats per minute for these women, choosing a suitable method.

Question 5. In a retail market, fruit vendors were selling mangoes kept in packing boxes. These boxes contained varying number of mangoes. The following was the distribution of mangoes according to the number of boxes. Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?

Question 6. The table below shows the daily expenditure on food of 25 households in a localityFind the mean daily expenditure on food by a suitable method.

Question 7. To find out the concentration of SO2 in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented below: Find the mean concentration of SO2 in the air.

Question 8. A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

Question 9. The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate

EXERCISE 14.2

Question 1. The following table shows the ages of the patients admitted in a hospital during a year: Find the mode and the mean of the data given above. Compare and interpret the two measures of central tendency.

Question 2. The following data gives the information on the observed lifetimes (in hours) of 225 electrical components : Determine the modal lifetimes of the components.

Question 3. The following data gives the distribution of total monthly household expenditure of 200 families of a village. Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure :

Question 4. The following distribution gives the state-wise teacher-student ratio in higher secondary schools of India. Find the mode and mean of this data. Interpret the two measures.

Question 5. The given distribution shows the number of runs scored by some top batsmen of the world in one-day international cricket matches Find the mode of the data.

Question 6. A student noted the number of cars passing through a spot on a road for 100 periods each of 3 minutes and summarised it in the table given below. Find the mode of the data :

EXERCISE 14.3

Question 1. The following frequency distribution gives the monthly consumption of electricity of 68 consumers of a locality. Find the median, mean and mode of the data and compare them.

Question 2. If the median of the distribution given below is 28.5, find the values of x and y

Question 3. A life insurance agent found the following data for distribution of ages of 100 policy holders. Calculate the median age, if policies are given only to persons having age 18 years onwards but less than 60 year.

Question 4. The lengths of 40 leaves of a plant are measured correct to the nearest millimetre, and the data obtained is represented in the following table Find the median length of the leaves. (Hint : The data needs to be converted to continuous classes for finding the median, since the formula assumes continuous classes. The classes then change to 117.5 - 126.5, 126.5 - 135.5, . . ., 171.5 - 180.5.)

Question 5. The following table gives the distribution of the life time of 400 neon lamps : Find the median life time of a lamp.

Question 6. 100 surnames were randomly picked up from a local telephone directory and the frequency distribution of the number of letters in the English alphabets in the surnames was obtained as follows: Determine the median number of letters in the surnames. Find the mean number of letters in the surnames? Also, find the modal size of the surnames.

Question 7. The distribution below gives the weights of 30 students of a class. Find the median weight of the students.

EXERCISE 14.4

Question 1. The following distribution gives the daily income of 50 workers of a factory. Convert the distribution above to a less than type cumulative frequency distribution, and draw its ogive.

Question 2. During the medical check-up of 35 students of a class, their weights were recorded as follows: Draw a less than type ogive for the given data. Hence obtain the median weight from the graph and verify the result by using the formula.

Question 3. The following table gives production yield per hectare of wheat of 100 farms of a village.

:: Chapter 15 Probability ::

EXERCISE 15.1

Question 1. Complete the following statements:

(i) Probability of an event E + Probability of the event ‘not E’ = .
(ii) The probability of an event that cannot happen is . Such an event is called .
(iii) The probability of an event that is certain to happen is . Such an event is called .
(iv) The sum of the probabilities of all the elementary events of an experiment is .
(v) The probability of an event is greater than or equal to and less than or equal to .

Question 2. Which of the following experiments have equally likely outcomes? Explain.

(i) A driver attempts to start a car. The car starts or does not start.
(ii) A player attempts to shoot a basketball. She/he shoots or misses the shot.
(iii) A trial is made to answer a true-false question. The answer is right or wrong.
(iv) A baby is born. It is a boy or a girl.

Question 3. Why is tossing a coin considered to be a fair way of deciding which team should get the ball at the beginning of a football game?

Question 4. Which of the following cannot be the probability of an event?

(A) 2 3
(B) –1.5
(C) 15%
(D) 0.7

Question 5. If P(E) = 0.05, what is the probability of ‘not E’?

Question 6. A bag contains lemon flavoured candies only. Malini takes out one candy without looking into the bag. What is the probability that she takes out

(i) an orange flavoured candy?
(ii) a lemon flavoured candy? 7. It is given that in a group of 3 students, the probability of 2 students not having the same birthday is 0.992. What is the probability that the 2 students have the same birthday?

Question 8. A bag contains 3 red balls and 5 black balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is

(i) red ?
(ii) not red?

Question 9. A box contains 5 red marbles, 8 white marbles and 4 green marbles. One marble is taken out of the box at random. What is the probability that the marble taken out will be

(i) red ?
(ii) white ?
(iii) not green?

Question 10. A piggy bank contains hundred 50p coins, fifty Re 1 coins, twenty Rs 2 coins and ten Rs 5 coins. If it is equally likely that one of the coins will fall out when the bank is turned upside down, what is the probability that the coin

(i) will be a 50 p coin ?
(ii) will not be a Rs 5 coin?

Question 11. Gopi buys a fish from a shop for his aquarium. The shopkeeper takes out one fish at random from a tank containing 5 male fish and 8 female fish (see Fig. 15.4). What is the probability that the fish taken out is a male fish?

Question 12. A game of chance consists of spinning an arrow which comes to rest pointing at one of the numbers 1, 2, 3, 4, 5, 6, 7, 8 (see Fig. 15.5 ), and these are equally likely outcomes. What is the probability that it will point at

(i) 8 ?
(ii) an odd number?
(iii) a number greater than 2?
(iv) a number less than 9?

Question 13. A die is thrown once. Find the probability of getting

(i) a prime number
(ii) a number lying between 2 and 6
(iii) an odd number.

Question 14. One card is drawn from a well-shuffled deck of 52 cards. Find the probability of getting

(i) a king of red colour
(ii) a face card
(iii) a red face card
(iv) the jack of hearts
(v) a spade
(vi) the queen of diamonds

Question15. Five cards—the ten, jack, queen, king and ace of diamonds, are well-shuffled with their face downwards. One card is then picked up at random.

(i) What is the probability that the card is the queen?
(ii) If the queen is drawn and put aside, what is the probability that the second card picked up is (a) an ace? (b) a queen?

Question 16. 12 defective pens are accidentally mixed with 132 good ones. It is not possible to just look at a pen and tell whether or not it is defective. One pen is taken out at random from this lot. Determine the probability that the pen taken out is a good one.

Question 17. (i) A lot of 20 bulbs contain 4 defective ones. One bulb is drawn at random from the lot. What is the probability that this bulb is defective?
(ii) Suppose the bulb drawn in (i) is not defective and is not replaced. Now one bulb is drawn at random from the rest. What is the probability that this bulb is not defective ?

Question 18. A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability that it bears

(i) a two-digit number
(ii) a perfect square number
(iii) a number divisible by 5.

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NCERT Chemistry Question Paper (Class - 11)

(Chemistry) Chapter 1 Some Basic Concepts Of Chemistry

NCERT Exercises Questions

Question 1.1 Calculate the molecular mass of the following :
(i) H2O
(ii) CO2
(iii) CH4

Question 1.2 Calculate the mass per cent of different elements present in sodium sulphate (Na2SO4).

Question 1.3 Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygen by mass.

Question 1.4 Calculate the amount of carbon dioxide that could be produced when
(i) 1 mole of carbon is burnt in air.
(ii) 1 mole of carbon is burnt in 16 g of dioxygen.
(iii) 2 moles of carbon are burnt in 16 g of dioxygen.

Question 1.5 Calculate the mass of sodium acetate (CH3COONa) required to make 500 mL of 0.375 molar aqueous solution. Molar mass of sodium acetate is 82.0245 g mol–1.

Question 1.6 Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the mass per cent of nitric acid in it being 69%.

Question 1.7 How much copper can be obtained from 100 g of copper sulphate (CuSO4) ?

Question 1.8 Determine the molecular formula of an oxide of iron in which the mass per cent of iron and oxygen are 69.9 and 30.1 respectively.

Question 1.9 Calculate the atomic mass (average) of chlorine using the following data : % Natural Abundance Molar Mass 35Cl 75.77 34.9689 37Cl 24.23 36.9659

Question 1.10 In three moles of ethane (C2H6), calculate the following :
(i) Number of moles of carbon atoms.
(ii) Number of moles of hydrogen atoms.
(iii) Number of molecules of ethane.

Question 1.11 What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final volume up to 2L?

Question 1.12 If the density of methanol is 0.793 kg L–1, what is its volume needed for making 2.5 L of its 0.25 M solution?

Question 1.13 Pressure is determined as force per unit area of the surface. The SI unit of pressure, pascal is as shown below : 1Pa = 1N m–2 If mass of air at sea level is 1034 g cm–2, calculate the pressure in pascal.

Question 1.14 What is the SI unit of mass? How is it defined?

Question 1.15 Match the following prefixes with their multiples: Prefixes Multiples
(i) micro 106
(ii) deca 109
(iii) mega 10–6
(iv) giga 10–15
(v) femto 10

Question 1.16 What do you mean by significant figures ?

Question 1.17 A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
(i) Express this in percent by mass.
(ii) Determine the molality of chloroform in the water sample.

Question 1.18 Express the following in the scientific notation:
(i) 0.0048
(ii) 234,000
(iii) 8008
(iv) 500.0
(v) 6.0012

Question 1.19 How many significant figures are present in the following?
(i) 0.0025
(ii) 208
(iii) 5005
(iv) 126,000
(v) 500.0
(vi) 2.0034

Question 1.20 Round up the following upto three significant figures:
(i) 34.216
(ii) 10.4107
(iii) 0.04597
(iv) 2808

Question 1.21 The following data are obtained when dinitrogen and dioxygen react together to form different compounds : Mass of dinitrogen Mass of dioxygen
(i) 14 g 16 g
(ii) 14 g 32 g
(iii) 28 g 32 g
(iv) 28 g 80 g

(a) Which law of chemical combination is obeyed by the above experimental data? Give its statement.
(b) Fill in the blanks in the following conversions:

(i) 1 km = ...................... mm = ...................... pm
(ii) 1 mg = ...................... kg = ...................... ng
(iii) 1 mL = ...................... L = ...................... dm3

Question 1.22 If the speed of light is 3.0 × 108 m s–1, calculate the distance covered by light in 2.00 ns.

Question 1.23 In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.
(i) 300 atoms of A + 200 molecules of B
(ii) 2 mol A + 3 mol B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 mol A + 2.5 mol B
(v)2.5 mol A + 5 mol B

Question 1.24 Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation: N2 (g) + H2 (g) → 2NH3 (g)
(i) Calculate the mass of ammonia produced if 2.00 × 103 g dinitrogen reacts with 1.00 ×103 g of dihydrogen.
(ii) Will any of the two reactants remain unreacted?
(iii) If yes, which one and what would be its mass?

Question 1.25 How are 0.50 mol Na2CO3 and 0.50 M Na2CO3 different?

Question 1.26 If ten volumes of dihydrogen gas reacts with five volumes of dioxygen gas, how many volumes of water vapour would be produced?

Question 1.27 Convert the following into basic units:
(i) 28.7 pm
(ii) 15.15 pm
(iii) 25365 mg

Question 1.28 Which one of the following will have largest number of atoms?
(i) 1 g Au (s)
(ii) 1 g Na (s)
(iii) 1 g Li (s)
(iv) 1 g of Cl2(g)

Question 1.29 Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.040.

Question 1.30 What will be the mass of one 12C atom in g ?

Question 1.31 How many significant figures should be present in the answer of the following calculations?
(i) 0.02856 29 0.5 ×
(ii) 5 × 5.364
(iii) 0.0125 + 0.7864 + 0.0215

Question 1.32 Use the data given in the following table to calculate the molar mass of naturally occuring argon isotopes: Isotope Isotopic molar mass Abundance 36Ar 35.96755 g mol–1 0.337% 38Ar 37.96272 g mol–1 0.063% 40Ar 39.9624 g mol–1 99.600%

Question 1.33 Calculate the number of atoms in each of the following
(i) 52 moles of Ar
(ii) 52 u of He
(iii) 52 g of He.

Question 1.34 A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g carbon dioxide , 0.690 g of water and no other products. A volume of 10.0 L (measured at STP) of this welding gas is found to weigh 11.6 g. Calculate (i) empirical formula, (ii) molar mass of the gas, and (iii) molecular formula.

Question 1.35 Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction, CaCO3 (s) + 2 HCl (aq) → CaCl2 (aq) + CO2(g) + H2O(l) What mass of CaCO3 is required to react completely with 25 mL of 0.75 M HCl?

Question 1.36 Chlorine is prepared in the laboratory by treating manganese dioxide (MnO2) with aqueous hydrochloric acid according to the reaction 4 HCl (aq) + MnO2(s) → 2H2O (l) + MnCl2(aq) + Cl2 (g) How many grams of HCl react with 5.0 g of manganese dioxide?

 

(Chemistry) Chapter 2 Structure Of Atom

NCERT Exercises Questions

Question 2.1 (i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.

Question 2.2 (i) Calculate the total number of electrons present in one mole of methane.
(ii) Find (a) the total number and (b) the total mass of neutrons in 7 mg of 14C. (Assume that mass of a neutron = 1.675 × 10–27 kg).
(iii) Find (a) the total number and (b) the total mass of protons in 34 mg of NH3 at STP. Will the answer change if the temperature and pressure are changed ?

Question 2.3 How many neutrons and protons are there in the following nuclei ?
13 16 24 6 8 12 C, O, Mg,

Question 2.4 Write the complete symbol for the atom with the given atomic number (Z) and atomic mass (A)
(i) Z = 17 , A = 35.
(ii) Z = 92 , A = 233.
(iii) Z = 4 , A = 9.

Question 2.5 Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (ν) and wavenumber ( ν ) of the yellow light.

Question 2.6 Find energy of each of the photons which
(i) correspond to light of frequency 3×1015 Hz.
(ii) have wavelength of 0.50 Å.

Question 2.7 Calculate the wavelength, frequency and wavenumber of a light wave whose period is 2.0 × 10–10 s.

Question 2.8 What is the number of photons of light with a wavelength of 4000 pm that provide 1J of energy?

Question 2.9 A photon of wavelength 4 × 10–7 m strikes on metal surface, the work function of the metal being 2.13 eV. Calculate (i) the energy of the photon (eV), (ii) the kinetic energy of the emission, and (iii) the velocity of the photoelectron (1 eV= 1.6020 × 10–19 J).

Question 2.10 Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom. Calculate the ionisation energy of sodium in kJ mol–1.

Question 2.11 A 25 watt bulb emits monochromatic yellow light of wavelength of 0.57μm. Calculate the rate of emission of quanta per second.

Question 2.12 Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. Calculate threshold frequency (ν0 ) and work function (W0 ) of the metal.

Question 2.13 What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?

Question 2.14 How much energy is required to ionise a H atom if the electron occupies n = 5 orbit? Compare your answer with the ionization enthalpy of H atom ( energy required to remove the electron from n =1 orbit).

Question 2.15 What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to the ground state?

Question 2.16 (i) The energy associated with the first orbit in the hydrogen atom is –2.18 × 10–18 J atom–1. What is the energy associated with the fifth orbit?
(ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.

Question 2.17 Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.

Question 2.18 What is the energy in joules, required to shift the electron of the hydrogen atom from the first Bohr orbit to the fifth Bohr orbit and what is the wavelength of the light emitted when the electron returns to the ground state? The ground state electron energy is –2.18 × 10–11 ergs.

Question 2.19 The electron energy in hydrogen atom is given by En = (–2.18 × 10–18 )/n2 J. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition?

Question 2.20 Calculate the wavelength of an electron moving with a velocity of 2.05 × 107 m s–1.

Question 2.21 The mass of an electron is 9.1 × 10–31 kg. If its K.E. is 3.0 × 10–25 J, calculate its wavelength.

Question 2.22 Which of the following are isoelectronic species i.e., those having the same number of electrons? Na+, K+, Mg2+, Ca2+, S2–, Ar.

Question 2.23 (i) Write the electronic configurations of the following ions:
(a) H–
(b) Na+
(c) O2–
(d) F–

(ii) What are the atomic numbers of elements whose outermost electrons are represented by
(a) 3s1
(b) 2p3
(c) 3p5 ?

(iii) Which atoms are indicated by the following configurations ?
(a) [He] 2s1
(b) [Ne] 3s2 3p3
(c) [Ar] 4s2 3d1.

Question 2.24 What is the lowest value of n that allows g orbitals to exist?

Question 2.25 An electron is in one of the 3d orbitals. Give the possible values of n, l and ml for this electron.

Question 2.26 An atom of an element contains 29 electrons and 35 neutrons. Deduce (i) the number of protons and (ii) the electronic configuration of the element.

Question 2.27 Give the number of electrons in the species H H andO 2 2 2 + , +

Question 2.28 (i) An atomic orbital has n = 3. What are the possible values of l and ml ?
(ii) List the quantum numbers (ml and l ) of electrons for 3d orbital.
(iii) Which of the following orbitals are possible? 1p, 2s, 2p and 3f

Question 2.29 Using s, p, d notations, describe the orbital with the following quantum numbers.
(a) n=1, l=0;
(b) n = 3; l=1
(c) n 4; l =2;
(d) n=4; l=3.

Question 2.30 Explain, giving reasons, which of the following sets of quantum numbers are not possible.
(a) n = 0, l = 0, ml = 0, ms = + ½
(b) n = 1, l = 0, ml = 0, ms = – ½
(c) n = 1, l = 1, ml = 0, ms = + ½
(d) n = 2, l = 1, ml = 0, ms = – ½
(e) n = 3, l = 3, ml = –3, ms = + ½
(f) n = 3, l = 1, ml = 0, ms = + ½

Question 2.31 How many electrons in an atom may have the following quantum numbers?
(a) n = 4, ms = – ½
(b) n = 3, l = 0

Question 2.32 Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit.

Question 2.33 What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He+ spectrum ?

Question 2.34 Calculate the energy required for the process He+ (g) He2+ (g) + e– The ionization energy for the H atom in the ground state is 2.18 × 10–18 J atom–1

Question 2.35 If the diameter of a carbon atom is 0.15 nm, calculate the number of carbon atoms which can be placed side by side in a straight line across length of scale of length 20 cm long.

Question 2.36 2 ×108 atoms of carbon are arranged side by side. Calculate the radius of carbon atom if the length of this arrangement is 2.4 cm.

Question 2.37 The diameter of zinc atom is 2.6 Å.Calculate (a) radius of zinc atom in pm and (b) number of atoms present in a length of 1.6 cm if the zinc atoms are arranged side by side lengthwise.

Question 2.38 A certain particle carries 2.5 × 10–16C of static electric charge. Calculate the number of electrons present in it.

Question 2.39 In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is –1.282 × 10–18C, calculate the number of electrons present on it.

Question 2.40 In Rutherford’s experiment, generally the thin foil of heavy atoms, like gold, platinum etc. have been used to be bombarded by the α-particles. If the thin foil of light atoms like aluminium etc. is used, what difference would be observed from the above results ?

Question 2.41 Symbols 79 35Br and 79Br can be written, whereas symbols 35 79 Br and 35Br are not acceptable. Answer briefly.

Question 2.42 An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.

Question 2.43 An ion with mass number 37 possesses one unit of negative charge. If the ion conatins 11.1% more neutrons than the electrons, find the symbol of the ion.

Question 2.44 An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol to this ion.

Question 2.45 Arrange the following type of radiations in increasing order of frequency:
(a) radiation from microwave oven (b) amber light from traffic signal (c) radiation from FM radio (d) cosmic rays from outer space and (e) X-rays.

Question 2.46 Nitrogen laser produces a radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 1024, calculate the power of this laser.

Question 2.47 Neon gas is generally used in the sign boards. If it emits strongly at 616 nm, calculate
(a) the frequency of emission (b) distance traveled by this radiation in 30 s (c) energy of quantum and (d) number of quanta present if it produces 2 J of energy.

Question 2.48 In astronomical observations, signals observed from the distant stars are generally

(Chemistry) Chapter 3 Classification of Elements and Periodicity in Properties

NCERT Exercises Questions

Question 3.1 What is the basic theme of organisation in the periodic table?

Question 3.2 Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

Question 3.3 What is the basic difference in approach between the Mendeleev’s Periodic Law and the Modern Periodic Law?

Question 3.4 On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

Question 3.5 In terms of period and group where would you locate the element with Z =114?

Question 3.6 Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Question 3.7 Which element do you think would have been named by
(i) Lawrence Berkeley Laboratory
(ii) Seaborg’s group?

Question 3.8 Why do elements in the same group have similar physical and chemical properties?

Question 3.9 What does atomic radius and ionic radius really mean to you?

Question 3.10 How do atomic radius vary in a period and in a group? How do you explain the variation?

Question 3.11 What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
(i) F–
(ii) Ar
(iii) Mg2+
(iv) Rb+

Question 3.12 Consider the following species : N3–, O2–, F–, Na+, Mg2+ and Al3+
(a) What is common in them?
(b) Arrange them in the order of increasing ionic radii.

Question 3.13 Explain why cation are smaller and anions larger in radii than their parent atoms?

Question 3.14 What is the significance of the terms — ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy? Hint : Requirements for comparison purposes.

Question 3.15 Energy of an electron in the ground state of the hydrogen atom is –2.18×10–18J. Calculate the ionization enthalpy of atomic hydrogen in terms of J mol–1. Hint: Apply the idea of mole concept to derive the answer.

Question 3.16 Among the second period elements the actual ionization enthalpies are in the order Li < B < Be < C < O < N < F < Ne. Explain why
(i) Be has higher Δi H than B
(ii) O has lower Δi H than N and F?

Question 3.17 How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

Question 3.18 What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?

Question 3.19 The first ionization enthalpy values (in kJ mol–1) of group 13 elements are : B Al Ga In Tl 801 577 579 558 589 How would you explain this deviation from the general trend ?

Question 3.20 Which of the following pairs of elements would have a more negative electron gain enthalpy?
(i) O or F
(ii) F or Cl

Question 3.21 Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

Question 3.22 What is the basic difference between the terms electron gain enthalpy and electronegativity?

Question 3.23 How would you react to the statement that the electronegativity of N on Pauling scale is Question 3.0 in all the nitrogen compounds?

Question 3.24 Describe the theory associated with the radius of an atom as it
(a) gains an electron
(b) loses an electron

Question 3.25 Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

Question 3.26 What are the major differences between metals and non-metals?

Question 3.27 Use the periodic table to answer the following questions.
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify an element that would tend to gain two electrons.
(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.

Question 3.28 The increasing order of reactivity among group 1 elements is Li < Na < K < Rb CI > Br > I. Explain.

Question 3.29 Write the general outer electronic configuration of s-, p-, d- and f- block elements.

Question 3.30 Assign the position of the element having outer electronic configuration
(i) ns2np4 for n=3
(ii) (n-1)d2ns2 for n=4, and
(iii) (n-2) f 7 (n-1)d1ns2 for n=6, in the periodic table.

Question 3.31 The first (ΔiH1) and the second (ΔiH2) ionization enthalpies (in kJ mol–1) and the (ΔegH) electron gain enthalpy (in kJ mol–1) of a few elements are given below: Elements ΔH1 ΔH2 ΔegH I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be :
(a) the least reactive element.
(b) the most reactive metal.
(c) the most reactive non-metal.
(d) the least reactive non-metal.
(e) the metal which can form a stable binary halide of the formula MX2(X=halogen).
(f) the metal which can form a predominantly stable covalent halide of the formula MX (X=halogen)?

Question 3.32 Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements.
(a) Lithium and oxygen
(b) Magnesium and nitrogen
(c) Aluminium and iodine
(d) Silicon and oxygen
(e) Phosphorus and fluorine
(f) Element 71 and fluorine

Question 3.33 In the modern periodic table, the period indicates the value of :
(a) atomic number
(b) atomic mass
(c) principal quantum number
(d) azimuthal quantum number.

Question 3.34 Which of the following statements related to the modern periodic table is incorrect?
(a) The p-block has 6 columns, because a maximum of 6 electrons can occupy all the orbitals in a p-shell.
(b) The d-block has 8 columns, because a maximum of 8 electrons can occupy all the orbitals in a d-subshell.
(c) Each block contains a number of columns equal to the number of electrons that can occupy that subshell.
(d) The block indicates value of azimuthal quantum number (l) for the last subshell that received electrons in building up the electronic configuration.

Question 3.35 Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?
(a) Valence principal quantum number (n)
(b) Nuclear charge (Z )
(c) Nuclear mass
(d) Number of core electrons.

Question 3.36 The size of isoelectronic species — F–, Ne and Na+ is affected by
(a) nuclear charge (Z )
(b) valence principal quantum number (n)
(c) electron-electron interaction in the outer orbitals
(d) none of the factors because their size is the same.

Question 3.37 Which one of the following statements is incorrect in relation to ionization enthalpy?
(a) Ionization enthalpy increases for each successive electron.
(b) The greatest increase in ionization enthalpy is experienced on removal of electron from core noble gas configuration.
(c) End of valence electrons is marked by a big jump in ionization enthalpy.
(d) Removal of electron from orbitals bearing lower n value is easier than from orbital having higher n value.

Question 3.38 Considering the elements B, Al, Mg, and K, the correct order of their metallic character is :
(a) B > Al > Mg > K
(b) Al > Mg > B > K
(c) Mg > Al > K > B
(d) K > Mg > Al > B

Question 3.39 Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is :
(a) B > C > Si > N > F
(b) Si > C > B > N > F
(c) F > N > C > B > Si
(d) F > N > C > Si > B

Question 3.40 Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is :
(a) F > Cl > O > N
(b) F > O > Cl > N
(c) Cl > F > O > N
(d) O > F > N > Cl

(Chemistry) Chapter 4 Chemical Bonding and Molecular Structure

NCERT Exercises Questions

Question 4.1 Explain the formation of a chemical bond.

Question 4.2 Write Lewis dot symbols for atoms of the following elements :
Mg, Na, B, O, N, Br.

Question 4.3 Write Lewis symbols for the following atoms and ions:
S and S2–; Al and Al3+; H and H–

Question 4.4 Draw the Lewis structures for the following molecules and ions :
H2S, SiCl4, BeF2, 2 3 CO − , HCOOH

Question 4.5 Define octet rule. Write its significance and limitations.

Question 4.6 Write the favourable factors for the formation of ionic bond.

Question 4.7 Discuss the shape of the following molecules using the VSEPR model:
BeCl2, BCl3, SiCl4, AsF5, H2S, PH3

Question 4.8 Although geometries of NH3 and H2O molecules are distorted tetrahedral, bond angle in water is less than that of ammonia. Discuss.

Question 4.9 How do you express the bond strength in terms of bond order ?

Question 4.10 Define the bond length.

Question 4.11 Explain the important aspects of resonance with reference to the 2 3 CO − ion.

Question 4.12 H3PO3 can be represented by structures 1 and 2 shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing H3PO3 ? If not, give reasons for the same.

Question 4.13 Write the resonance structures for SO3, NO2 and 3 NO− .

Question 4.14 Use Lewis symbols to show electron transfer between the following atoms to form cations and anions : (a) K and (b) Ca and O (c) Al and N.

Question 4.15 Although both CO2 and H2O are triatomic molecules, the shape of H2O molecule is bent while that of CO2 is linear. Explain this on the basis of dipole moment. 4.16 Write the significance/applications of dipole moment.

Question 4.17 Define electronegativity. How does it differ from electron gain enthalpy ?

Question 4.18 Explain with the help of suitable example polar covalent bond.

Question 4.19 Arrange the bonds in order of increasing ionic character in the molecules: LiF, K2O, N2, SO2 and ClF3.

Question 4.20 The skeletal structure of CH3COOH as shown below is correct, but some of the bonds are shown incorrectly. Write the correct Lewis structure for acetic acid.

Question 4.21 Apart from tetrahedral geometry, another possible geometry for CH4 is square planar with the four H atoms at the corners of the square and the C atom at its centre. Explain why CH4 is not square planar ?
Question 4.22 Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.

Question 4.23 Which out of NH3 and NF3 has higher dipole moment and why ?

Question 4.24 What is meant by hybridisation of atomic orbitals? Describe the shapes of sp, sp2, sp3 hybrid orbitals.

Question 4.25 Describe the change in hybridisation (if any) of the Al atom in the following reaction. 3 AlCl + Cl− → Al

Question 4.26 Is there any change in the hybridisation of B and N atoms as a result of the following reaction ? 3 3 3 BF + NH → F B

Question 4.27 Draw diagrams showing the formation of a double bond and a triple bond between carbon atoms in C2H4 and C2H2 molecules.

Question 4.28 What is the total number of sigma and pi bonds in the following molecules ?
(a) C2H2
(b) C2H4

Question 4.29 Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?
(a) 1s and 1s
(b) 1s and 2px ;
(c) 2py and 2py
(d) 1s and 2s.

Question 4.30 Which hybrid orbitals are used by carbon atoms in the following molecules ?
(a)CH3–CH3;
(b) CH3–CH=CH2;
(c) CH3-CH2-OH;
(d) CH3-CHO
(e) CH3COOH

Question 4.31 What do you understand by bond pairs and lone pairs of electrons ? Illustrate by giving one exmaple of each type.

Question 4.32 Distinguish between a sigma and a pi bond.

Question 4.33 Explain the formation of H2 molecule on the basis of valence bond theory.

Question 4.34 Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals.

Question 4.35 Use molecular orbital theory to explain why the Be2 molecule does not exist.4.36 Compare the relative stability of the following species and indicate their magnetic properties; 2 2 2 O ,O+ ,O− (superoxide), 2 2 O − (peroxide)

Question 4.37 Write the significance of a plus and a minus sign shown in representing the orbitals.

Question 4.38 Describe the hybridisation in case of PCl5. Why are the axial bonds longer as compared to equatorial bonds ?

Question 4.39 Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

Question 4.40 What is meant by the term ond order ? Calculate the bond order of : N2, O2, O2 + and O2

(Chemistry) Chapter 5 States Of Matter

NCERT Solutions Questions

Question 5.1 What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C? 152 C:\ChemistryXI\Unit-5\Unit-5(4)-Lay-2.pmd 14.1.6 (Final), 17.1.6, 24.1.6

Question 5.2 A vessel of 120 mL capacity contains a certain amount of gas at 35 °C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35 °C. What would be its pressure?

Question 5.3 Using the equation of state pV=nRT; show that at a given temperature density of a gas is proportional to gas pressure p.

Question 5.4 At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

Question 5.5 Pressure of 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 g of another ideal gas B is introduced in the same flask at same temperature the pressure becomes 3 bar. Find a relationship between their molecular masses.

Question 5.6 The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15g of aluminum reacts?

Question 5.7 What will be the pressure exerted by a mixture of 3.2 g of methane and 4.4 g of carbon dioxide contained in a 9 dm3 flask at 27 °C ?

Question 5.8 What will be the pressure of the gaseous mixture when 0.5 L of H2 at 0.8 bar and 2.0 L of dioxygen at 0.7 bar are introduced in a 1L vessel at 27°C?

Question 5.9 Density of a gas is found to be 5.46 g/dm3 at 27 °C at 2 bar pressure. What will be its density at STP?

Question 5.10 34.05 mL of phosphorus vapour weighs 0.0625 g at 546 °C and 0.1 bar pressure. What is the molar mass of phosphorus?

Question 5.11 A student forgot to add the reaction mixture to the round bottomed flask at 27 °C but instead he/she placed the flask on the flame. After a lapse of time, he realized his mistake, and using a pyrometer he found the temperature of the flask was 477 °C. What fraction of air would have been expelled out?

Question 5.12 Calculate the temperature of 4.0 mol of a gas occupying 5 dm3 at 3.32 bar. (R = 0.083 bar dm3 K–1 mol–1).

Question 5.13 Calculate the total number of electrons present in 1.4 g of dinitrogen gas.

Question 5.14 How much time would it take to distribute one Avogadro number of wheat grains, if 1010 grains are distributed each second ?

Question 5.15 Calculate the total pressure in a mixture of 8 g of dioxygen and 4 g of dihydrogen confined in a vessel of 1 dm3 at 27°C. R = 0.083 bar dm3 K–1 mol–1.

Question 5.16 Pay load is defined as the difference between the mass of displaced air and the mass of the balloon. Calculate the pay load when a balloon of radius 10 m, mass 100 kg is filled with helium at 1.66 bar at 27°C. (Density of air = 1.2 kg m–3 and R = 0.083 bar dm3 K–1 mol–1).

Question 5.17 Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure. R = 0.083 bar L K–1 mol–1.

Question 5.18 2.9 g of a gas at 95 °C occupied the same volume as 0.184 g of dihydrogen at 17 °C, at the same pressure. What is the molar mass of the gas?

Question 5.19 A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen. Calculate the partial pressure of dihydrogen.

Question 5.20 What would be the SI unit for the quantity pV 2T 2/n ?

Question 5.21 In terms of Charles’ law explain why –273 °C is the lowest possible temperature.

Question 5.22 Critical temperature for carbon dioxide and methane are 31.1 °C and –81.9 °C respectively. Which of these has stronger intermolecular forces and why?

Question 5.23 Explain the physical significance of van der Waals parameters.

(Chemistry) Chapter 6 Thermodynamics

NCERT  Exercises Questions

Question 6. 1 Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.

Question 6. 2 For the process to occur under adiabatic conditions, the correct condition is:
(i) ΔT = 0
(ii) Δp = 0
(iii) q = 0
(iv) w = 0

Question 6. 3 The enthalpies of all elements in their standard states are:
(i) unity
(ii) zero
(iii) < 0
(iv) different for each element

Question 6. 4 ΔU0of combustion of methane is – X kJ mol–1. The value of ΔH0 is
(i) = ΔU0
(ii) > ΔU0
(iii) < ΔU0
(iv) = 0

Question 6. 5 The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, –890.3 kJ mol–1 –393.5 kJ mol–1, and –285.8 kJ mol–1 respectively. Enthalpy of formation of CH4(g) will be
(i) –74.8 kJ mol–1
(ii) –52.27 kJ mol–1
(iii) +74.8 kJ mol–1
(iv) +52.26 kJ mol–1.

Question 6. 6 A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(v) possible at any temperature

Question 6. 7 In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process?

Question 6. 8 The reaction of cyanamide, NH2CN (s), with dioxygen was carried out in a bomb calorimeter, and ΔU was found to be –742.7 kJ mol–1 at 298 K. Calculate enthalpy change for the reaction at 298 K. NH2CN(g) + 3 2 O2(g) → N2(g) + CO2(g) + H2O(l)

Question 6. 9 Calculate the number of kJ of heat necessary to raise the temperature of 60.0 g of aluminium from 35°C to 55°C. Molar heat capacity of Al is 24 J mol–1 K–1.

Question 6. 10 Calculate the enthalpy change on freezing of 1.0 mol of water at10.0°C to ice at –10.0°C. ΔfusH =

Question 6. 03 kJ mol–1 at 0°C. Cp [H2O(l)] = 75.3 J mol–1 K–1 Cp [H2O(s)] = 3Question 6. 8 J mol–1 K–1

Question 6. 11 Enthalpy of combustion of carbon to CO2 is –393.5 kJ mol–1. Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.

Question 6. 12 Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4(g) are –110, – 393, 81 and 9.7 kJ mol–1 respectively. Find the value of ΔrH for the reaction:
N2O4(g) + 3CO(g) → N2O(g) + 3CO2(g)

Question 6. 13 Given N2(g) + 3H2(g) → 2NH3(g) ; ΔrH0 = –92.4 kJ mol–1 What is the standard enthalpy of formation of NH3 gas?

Question 6. 14 Calculate the standard enthalpy of formation of CH3OH(l) from the following data: CH3OH (l) + 3 2 O2(g) → CO2(g) + 2H2O(l) ; ΔrH0 = –726 kJ mol–1 C(g) + O2(g) → CO2(g) ; ΔcH0 = –393 kJ mol–1 H2(g) + 1 2 O2(g) → H2O(l) ; Δf H0 = –286 kJ mol–1.

Question 6. 15 Calculate the enthalpy change for the process CCl4(g) → C(g) + 4 Cl(g) and calculate bond enthalpy of C – Cl in CCl4(g). ΔvapH0(CCl4) = 30.5 kJ mol–1. ΔfH0 (CCl4) = –135.5 kJ mol–1. ΔaH0 (C) = 715.0 kJ mol–1 , where ΔaH0 is enthalpy of atomisation ΔaH0 (Cl2) = 242 kJ mol–1 Question 6. 16 For an isolated system, ΔU = 0, what will be ΔS ?

Question 6. 17 For the reaction at 298 K, 2A + B → C ΔH = 400 kJ mol–1 and ΔS = 0.2 kJ K–1 mol–1 At what temperature will the reaction become spontaneous considering ΔH and ΔS to be constant over the temperature range.

Question 6. 18 For the reaction, 2 Cl(g) → Cl2(g), what are the signs of ΔH and ΔS ?


Question 6. 19 For the reaction 2 A(g) + B(g) → 2D(g) ΔU 0 = –10.5 kJ and ΔS0 = –44.1 JK–1. Calculate ΔG0 for the reaction, and predict whether the reaction may occur spontaneously.

Question 6. 20 The equilibrium constant for a reaction is 10. What will be the value of ΔG0 ? R = 8.314 JK–1 mol–1, T = 300 K.

Question 6. 21 Comment on the thermodynamic stability of NO(g), given 1 2 N2(g) + 1 2 O2(g) → NO(g) ; ΔrH0 = 90 kJ mol–1 NO(g) + 1 2 O2(g) → NO2(g) : ΔrH0= –74 kJ mol–1

Question 6. 22 Calculate the entropy change in surroundings when 1.00 mol of H2O(l) is formed under standard conditions. Δf H0 = –286 kJ mol–1.

(Chemistry) Chapter 7 Equilibrium

NCERT  Exercises Questions

Question 7.1 A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Question 7.2 What is Kc for the following equilibrium when the equilibrium concentration of each substance is:
[SO2]= 0.60M, [O2] = 0.82M and [SO3] = 1.90M ? 2SO2(g) + O2(g) ƒ 2SO3(g)

Question 7.3 At a certain temperature and total pressure of 105Pa, iodine vapour contains 40% by volume of I atoms I2 (g) ƒ 2I(g) Calculate Kp for the equilibrium.

Question 7.4 Write the expression for the equilibrium constant, Kc for each of the following reactions:
(i) 2NOCl (g) ƒ 2NO (g) + Cl2 (g)
(ii) 2Cu(NO3)2 (s) ƒ 2CuO (s) + 4NO2 (g) + O2 (g)
(iii) CH3COOC2H5(aq) + H2O(l) ƒ CH3COOH (aq) + C2H5OH (aq)
(iv) Fe3+ (aq) + 3OH– (aq) ƒ Fe(OH)3 (s) (v) I2 (s) + 5F2 ƒ 2IF5

Question 7.5 Find out the value of Kc for each of the following equilibria from the value of Kp:
(i) 2NOCl (g) ƒ 2NO (g) + Cl2 (g); Kp= 1.8 × 10–2 at 500 K
(ii) CaCO3 (s) ƒ CaO(s) + CO2(g); Kp= 167 at 1073 K

Question 7.6 For the following equilibrium, Kc= 6.3 × 1014 at 1000 K NO (g) + O3 (g) ƒ NO2 (g) + O2 (g) Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is Kc, for the reverse reaction?

Question 7.7 Explain why pure liquids and solids can be ignored while writing the equilibrium constant expression?

Question 7.8 Reaction between N2 and O2– takes place as follows: 2N2 (g) + O2 (g) ƒ 2N2O (g) If a mixture of 0.482 mol N2 and 0.933 mol of O2 is placed in a 10 L reaction vessel and allowed to form N2O at a temperature for which Kc= 2.0 × 10–37, determine the composition of equilibrium mixture. \

Question 7.9 Nitric oxide reacts with Br2 and gives nitrosyl bromide as per reaction given below: 2NO (g) + Br2 (g) ƒ 2NOBr (g) When 0.087 mol of NO and 0.0437 mol of Br2 are mixed in a closed container at constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate equilibrium amount of NO and Br2 .

Question 7.10 At 450K, Kp= 2.0 × 1010/bar for the given reaction at equilibrium. 2SO2(g) + O2(g) ƒ 2SO3 (g) What is Kc at this temperature ?

Question 7.11 A sample of HI(g) is placed in flask at a pressure of 0.2 atm. At equilibrium the partial pressure of HI(g) is 0.04 atm. What is Kp for the given equilibrium ? 2HI (g) ƒ H2 (g) + I2 (g)

Question 7.12 A mixture of 1.57 mol of N2, 1.92 mol of H2 and 8.13 mol of NH3 is introduced into a 20 L reaction vessel at 500 K. At this temperature, the equilibrium constant, Kc for the reaction N2 (g) + 3H2 (g) ƒ 2NH3 (g) is 1.7 × 102. Is the reaction mixture at equilibrium? If not, what is the direction of the net reaction?

Question 7.13 The equilibrium constant expression for a gas reaction is, [ ][ [ ] [ 4 3 2 4 2 NH O NO H O = c K Write the balanced chemical equation corresponding to this expression.

Question 7.14 One mole of H2O and one mole of CO are taken in 10 L vessel and heated to 725 K. At equilibrium 40% of water (by mass) reacts with CO according to the equation, H2O (g) + CO (g) ƒ H2 (g) + CO2 (g) Calculate the equilibrium constant for the reaction.

Question 7.15 At 700 K, equilibrium constant for the reaction: H2 (g) + I2 (g) ƒ 2HI (g) is 54.8. If 0.5 mol L–1 of HI(g) is present at equilibrium at 700 K, what are the concentration of H2(g) and I2(g) assuming that we initially started with HI(g) and allowed it to reach equilibrium at 700K?

Question 7.16 What is the equilibrium concentration of each of the substances in the equilibrium when the initial concentration of ICl was 0.78 M ? 2ICl (g) ƒ I2 (g) + Cl2 (g); Kc = 0.14

Question 7.17 Kp = 0.04 atm at 899 K for the equilibrium shown below. What is the equilibrium concentration of C2H6 when it is placed in a flask at 4.0 atm pressure and allowed to come to equilibrium? C2H6 (g) ƒ C2H4 (g) + H2 (g)

Question 7.18 Ethyl acetate is formed by the reaction between ethanol and acetic acid and the equilibrium is represented as: CH3COOH (l) + C2H5OH (l) ƒ CH3COOC2H5 (l) + H2O (l)
(i) Write the concentration ratio (reaction quotient), Qc, for this reaction (note: water is not in excess and is not a solvent in this reaction)
(ii) At 293 K, if one starts with 1.00 mol of acetic acid and 0.18 mol of ethanol, there is 0.171 mol of ethyl acetate in the final equilibrium mixture. Calculate the equilibrium constant.
(iii) Starting with 0.5 mol of ethanol and 1.0 mol of acetic acid and maintaining it at 293 K, 0.214 mol of ethyl acetate is found after sometime. Has equilibrium been reached?

Question 7.19 A sample of pure PCl5 was introduced into an evacuated vessel at 473 K. After equilibrium was attained, concentration of PCl5 was found to be 0.5 × 10–1 mol L–1. If value of Kc is 8.3 × 10–3, what are the concentrations of PCl3 and Cl2 at equilibrium? PCl5 (g) ƒ PCl3 (g) + Cl2(g)

Question 7.20 One of the reaction that takes place in producing steel from iron ore is the reduction of iron(II) oxide by carbon monoxide to give iron metal and CO2. FeO (s) + CO (g) ƒ Fe (s) + CO2 (g); Kp = 0.265 atm at 1050K What are the equilibrium partial pressures of CO and CO2 at 1050 K if the initial partial pressures are: pCO= 1.4 atm and CO2 p =0.80 atm?

Question 7.21 Equilibrium constant, Kc for the reaction N2 (g) + 3H2 (g) ƒ 2NH3 (g) at 500 K is 0.061 At a particular time, the analysis shows that composition of the reaction mixture is 3.0 mol L–1 N2, 2.0 mol L–1 H2 and 0.5 mol L–1 NH3. Isthe reaction at equilibrium? If not in which direction does the reaction tend to proceed to reach equilibrium?


Question 7.22 Bromine monochloride, BrCl decomposes into bromine and chlorine and reaches the equilibrium: 2BrCl (g) ƒ Br2 (g) + Cl2 (g) for which Kc= 32 at 500 K. If initially pure BrCl is present at a concentration of 3.3 × 10–3 mol L–1, what is its molar concentration in the mixture at equilibrium?


Question 7.23 At 1127 K and 1 atm pressure, a gaseous mixture of CO and CO2 in equilibrium with soild carbon has 90.55% CO by mass C (s) + CO2 (g) ƒ 2CO (g) Calculate Kc for this reaction at the above temperature.

Question 7.24 Calculate a) ΔG0 and b) the equilibrium constant for the formation of NO2 from NO and O2 at 298K NO (g) + ½ O2 (g) ƒ NO2 (g) where ΔfG0 (NO2) = 52.0 kJ/mol ΔfG0 (NO) = 87.0 kJ/mol ΔfG0 (O2) = 0 kJ/mol

Question 7.25 Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?
(a) PCl5 (g) ƒ PCl3 (g) + Cl2 (g)
(b) CaO (s) + CO2 (g) ƒ CaCO3 (s)
(c) 3Fe (s) + 4H2O (g) ƒ Fe3O4 (s) + 4H2 (g)

Question 7.26 Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
(i) COCl2 (g) ƒ CO (g) + Cl2 (g)
(ii) CH4 (g) + 2S2 (g) ƒ CS2 (g) + 2H2S (g)
(iii) CO2 (g) + C (s) ƒ 2CO (g) (iv) 2H2 (g) + CO (g) ƒ CH3OH (g )
(v) CaCO3 (s) ƒ CaO (s) + CO2 (g)
(vi) 4 NH3 (g) + 5O2 (g) ƒ 4NO (g) + 6H2O(g)

Question 7.27 The equilibrium constant for the following reaction is 1.6 ×105 at 1024K H2(g) + Br2(g) ƒ 2HBr(g) Find the equilibrium pressure of all gases if 10.0 bar of HBr is introduced into a sealed container at 1024K.

Question28 Dihydrogen gas is obtained from natural gas by partial oxidation with steam as per following endothermic reaction: CH4 (g) + H2O (g) ƒ CO (g) + 3H2 (g)
(a) Write as expression for Kp for the above reaction.
(b) How will the values of Kp and composition of equilibrium mixture be affected by
(i) increasing the pressure
(ii) increasing the temperature
(iii) using a catalyst ?

Question 7.29 Describe the effect of : a) addition of H2 b) addition of CH3OH c) removal of CO d) removal of CH3OH on the equilibrium of the reaction:
2H2(g) + CO (g) ƒ CH3OH (g)

Question 7.30 At 473 K, equilibrium constant Kc for decomposition of phosphorus pentachloride, PCl5 is 8.3 ×10-3. If decomposition is depicted as, PCl5 (g) ƒ PCl3 (g) + Cl2 (g) ΔrH0 = 124.0 kJ mol–1

a) write an expression for Kc for the reaction.
b) what is the value of Kc for the reverse reaction at the same temperature ?
c) what would be the effect on Kc if

(i) more PCl5 is added
(ii) pressure is increased
(iii) the temperature is increased ?

Question 7.31 Dihydrogen gas used in Haber’s process is produced by reacting methane from natural gas with high temperature steam. The first stage of two stage reaction involves the formation of CO and H2. In second stage, CO formed in first stage is reacted with more steam in water gas shift reaction, CO (g) + H2O (g) ƒ CO2 (g) + H2 (g) If a reaction vessel at 400 °C is charged with an equimolar mixture of CO and steam such that CO H2O p = p = 4.0 bar, what will be the partial pressure of H2 at equilibrium? Kp= 10.1 at 400°C

Question 7.32 Predict which of the following reaction will have appreciable concentration of reactants and products: a) Cl2 (g) ƒ 2Cl (g) Kc = 5 ×10–39 b) Cl2 (g) + 2NO (g) ƒ 2NOCl (g) Kc = 3.7 × 108 c) Cl2 (g) + 2NO2 (g) ƒ 2NO2Cl (g) Kc = 1.8

Question 7.33 The value of Kc for the reaction 3O2 (g) ƒ 2O3 (g) is 2.0 ×10–50 at 25°C. If the equilibrium concentration of O2 in air at 25°C is 1.6 ×10–2, what is the concentration of O3?

Question 7.34 The reaction, CO(g) + 3H2(g) ƒ CH4(g) + H2O(g) is at equilibrium at 1300 K in a 1L flask. It also contain 0.30 mol of CO, 0.10 mol of H2 and 0.02 mol of H2O and an unknown amount of CH4 in the flask. Determine the concentration of CH4 in the mixture. The equilibrium constant, Kc for the reaction at the given temperature is 3.90.

Question 7.35 What is meant by the conjugate acid-base pair? Find the conjugate acid/base for the following species: HNO2, CN–, HClO4, F –, OH–, CO3 2–, and S2–

Question 7.36 Which of the followings are Lewis acids? H2O, BF3, H+, and NH4 + 7.37 What will be the conjugate bases for the Brönsted acids: HF, H2SO4 and HCO3? 7.38 Write the conjugate acids for the following Brönsted bases: NH2 –, NH3 and HCOO–.

Question 7.39 The species: H2O, HCO3 –, HSO4 – and NH3 can act both as Brönsted acids and bases. For each case give the corresponding conjugate acid and base.

Question 7.40 Classify the following species into Lewis acids and Lewis bases and show how these act as Lewis acid/base:
(a) OH–
(b) F–
(c) H+
(d) BCl3 .

Question 7.41 The concentration of hydrogen ion in a sample of soft drink is 3.8 × 10–3 M. what is its pH?

Question 7.42 The pH of a sample of vinegar is 3.76. Calculate the concentration of hydrogen ion in it.

Question 7.43 The ionization constant of HF, HCOOH and HCN at 298K are 6.8 × 10–4, 1.8 × 10–4 and 4.8 × 10–9 respectively. Calculate the ionization constants of the corresponding conjugate base.

Question 7.44 The ionization constant of phenol is 1.0 × 10–10. What is the concentration of phenolate ion in 0.05 M solution of phenol? What will be its degree of ionization if the solution is also 0.01M in sodium phenolate?

Question 7.45 The first ionization constant of H2S is 9.1 × 10–8. Calculate the concentration of HS– ion in its 0.1M solution. How will this concentration be affected if the solution is 0.1M in HCl also ? If the second dissociation constant of H2S is 1.2 × 10–13, calculate the concentration of S2– under both conditions.

Question 7.46 The ionization constant of acetic acid is 1.74 × 10–5. Calculate the degree of dissociation of acetic acid in its 0.05 M solution. Calculate the concentration of acetate ion in the solution and its pH.

Question 7.47 It has been found that the pH of a 0.01M solution of an organic acid is 4.15. Calculate the concentration of the anion, the ionization constant of the acid and its pKa .

Question 7.48 Assuming complete dissociation, calculate the pH of the following solutions:
(a) 0.003 M HCl
(b) 0.005 M NaOH
(c) 0.002 M HBr
(d) 0.002 M KOH

Question 7.49 Calculate the pH of the following solutions:

a) 2 g of TlOH dissolved in water to give 2 litre of solution.
b) 0.3 g of Ca(OH)2 dissolved in water to give 500 mL of solution.
c) 0.3 g of NaOH dissolved in water to give 200 mL of solution.
d) 1mL of 13.6 M HCl is diluted with water to give 1 litre of solution.

Question 7.50 The degree of ionization of a 0.1M bromoacetic acid solution is 0.132. Calculate the pH of the solution and the pKa of bromoacetic acid.

Question 7.51 The pH of 0.005M codeine (C18H21NO3) solution is 9.95. Calculate its ionization constant and pKb.

Question 7.52 What is the pH of 0.001M aniline solution ? The ionization constant of aniline can be taken from Table7. Calculate the degree of ionization of aniline in the solution. Also calculate the ionization constant of the conjugate acid of aniline.

Question 7.53 Calculate the degree of ionization of 0.05M acetic acid if its pKa value is 4.74. How is the degree of dissociation affected when its solution also contains (a) 0.01M (b) 0.1M in HCl ?

Question 7.54 The ionization constant of dimethylamine is 5.4 × 10–4. Calculate its degree of ionization in its 0.02M solution. What percentage of dimethylamine is ionized if the solution is also 0.1M in NaOH?

Question 7.55 Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
(a) Human muscle-fluid, 6.83
(b) Human stomach fluid, 1.2
(c) Human blood,7.38
(d) Human saliva, 6.4.

Question 7.56 The pH of milk, black coffee, tomato juice, lemon juice and egg white are 6.8, 5.0, 4.2, 2.2 and 7.8 respectively. Calculate corresponding hydrogen ion concentration in each.

Question 7.57 If 0.561 g of KOH is dissolved in water to give 200 mL of solution at 298 K. Calculate the concentrations of potassium, hydrogen and hydroxyl ions. What is its pH?

Question 7.58 The solubility of Sr(OH)2 at 298 K is 19.23 g/L of solution. Calculate the concentrations of strontium and hydroxyl ions and the pH of the solution. \

Question 7.59 The ionization constant of propanoic acid is 1.32 × 10–5. Calculate the degree of ionization of the acid in its 0.05M solution and also its pH. What will be its degree of ionization if the solution is 0.01M in HCl also?

Question 7.60 The pH of 0.1M solution of cyanic acid (HCNO) is 2.34. Calculate the ionization constant of the acid and its degree of ionization in the solution.

Question 7.61 The ionization constant of nitrous acid is 4.5 × 10–4. Calculate the pH of 0.04 M sodium nitrite solution and also its degree of hydrolysis.

Question 7.62 A 0.02M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization constant of pyridine.

Question 7.63 Predict if the solutions of the following salts are neutral, acidic or basic: NaCl, KBr, NaCN, NH4NO3, NaNO2 and KF

Question 7.64 The ionization constant of chloroacetic acid is 1.35 × 10–3. What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Question 7.65 Ionic product of water at 310 K is 2.7 × 10–14. What is the pH of neutral water at this temperature?

Question 7.66 Calculate the pH of the resultant mixtures:
a) 10 mL of 0.2M Ca(OH)2 + 25 mL of 0.1M HCl
b) 10 mL of 0.01M H2SO4 + 10 mL of 0.01M Ca(OH)2
c) 10 mL of 0.1M H2SO4 + 10 mL of 0.1M KOH

Question 7.67 Determine the solubilities of silver chromate, barium chromate, ferric hydroxide, lead chloride and mercurous iodide at 298K from their solubility product constants given in Table Determine also the molarities of individual ions.

Question 7.68 The solubility product constant of Ag2CrO4 and AgBr are 1.1 × 10–12 and 5.0 × 10–13 respectively. Calculate the ratio of the molarities of their saturated solutions.

Question 7.69 Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate Ksp = 4 × 10–8 ).

Question 7.70 The ionization constant of benzoic acid is 6.46 × 10–5 and Ksp for silver benzoate is 2.5 × 10–13. How many times is silver benzoate more soluble in a buffer of pH 3.19 compared to its solubility in pure water?

Question 7.71 What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide so that when mixed in equal volumes, there is no precipitation of iron sulphide? (For iron sulphide, Ksp = 6.3 × 10–18).

Question 7.72 What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1 × 10–6).

Question 7.73 The concentration of sulphide ion in 0.1M HCl solution saturated with hydrogen sulphide is 1.0 × 10–19 M. If 10 mL of this is added to 5 mL of 0.04 M solution of the following: FeSO4, MnCl2, ZnCl2 and CdCl2. in which of these solutions precipitation will take place?

(Chemistry) Chapter 8 Redox Reactions

NCERT Exercises Questions

Question 8. 1 Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O


Question 8. 2 What are the oxidation number of the underlined elements in each of the following and how do you rationalise your results ?
(a) KI3
(b) H2S4O6
(c) Fe3O4
(d) CH3CH2OH
(e) CH3COOH


Question 8. 3 Justify that the following reactions are redox reactions:
(a) CuO(s) + H2(g) → Cu(s) + H2O(g)
(b) Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)
(c) 4BCl3(g) + 3LiAlH4(s) → 2B2H6(g) + 3LiCl(s) + 3 AlCl3 (s)
(d) 2K(s) + F2(g) → 2K+F– (s) (e) 4 NH3(g) + 5 O2(g) → 4NO(g) + 6H2O(g)


Question 8. 4 Fluorine reacts with ice and results in the change: H2O(s) + F2(g) → HF(g) + HOF(g) Justify that this reaction is a redox reaction.


Question 8. 5 Calculate the oxidation number of sulphur, chromium and nitrogen in H2SO5, Cr2O7 2– and NO3 –. Suggest structure of these compounds. Count for the fallacy.

Question 8. 6 Write formulas for the following compounds:
(a) Mercury(II) chloride
(b) Nickel(II) sulphate
(c) Tin(IV) oxide
(d) Thallium(I) sulphate
(e) Iron(III) sulphate
(f) Chromium(III) oxide

Question 8. 7 Suggest a list of the substances where carbon can exhibit oxidation states from –4 to +4 and nitrogen from –3 to +5.

Question 8. 8 While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why ?

Question 8. 9 Consider the reactions:
(a) 6 CO2(g) + 6H2O(l) → C6 H12 O6(aq) + 6O2(g)(b) O3(g) + H2O2(l) → H2O(l) + 2O2(g) Why it is more appropriate to write these reactions as : (a) 6CO2(g) + 12H2O(l) → C6 H12 O6(aq) + 6H2O(l) + 6O2(g) (b) O3(g) + H2O2 (l) → H2O(l) + O2(g) + O2(g) Also suggest a technique to investigate the path of the above (a) and (b) redox reactions.

Question 8. 10 The compound AgF2 is unstable compound. However, if formed, the compound acts as a very strong oxidising agent. Why ?

Question 8. 11 Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations.

Question 8. 12 How do you count for the following observations ?
(a) Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why ? Write a balanced redox equation for the reaction.
(b) When concentrated sulphuric acid is added to an inorganic mixture containing chloride, we get colourless pungent smelling gas HCl, but if the mixture contains bromide then we get red vapour of bromine. Why ?

Question 8. 13 Identify the substance oxidised reduced, oxidising agent and reducing agent for each of the following reactions:
(a) 2AgBr (s) + C6H6O2(aq) → 2Ag(s) + 2HBr (aq) + C6H4O2(aq)
(b) HCHO(l) + 2[Ag (NH3)2]+(aq) + 3OH–(aq) → 2Ag(s) + HCOO–(aq) + 4NH3(aq) + 2H2O(l)
(c) HCHO (l) + 2 Cu2+(aq) + 5 OH–(aq) → Cu2O(s) + HCOO–(aq) + 3H2O(l)
(d) N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(l) (e) Pb(s) + PbO2(s) + 2H2SO4(aq) → 2PbSO4(s) + 2H2O(l)

Question 8. 14 Consider the reactions : 2 S2O3 2– (aq) + I2(s) → S4 O6 2–(aq) + 2I–(aq) S2O3 2–(aq) + 2Br2(l) + 5 H2O(l) → 2SO4 2–(aq) + 4Br–(aq) + 10H+(aq) Why does the same reductant, thiosulphate react differently with iodine and bromine ?

Question 8. 15 Justify giving reactions that among halogens, fluorine is the best oxidant and among hydrohalic compounds, hydroiodic acid is the best reductant. What inference do you draw about the behaviour of Ag+ and Cu2+ from these reactions ?

Question 8. 18 Balance the following redox reactions by ion – electron method :
(a) MnO4 – (aq) + I– (aq) → MnO2 (s) + I2(s) (in basic medium)
(b) MnO4 – (aq) + SO2 (g) → Mn2+ (aq) + HSO4 – (aq) (in acidic solution)
(c) H2O2 (aq) + Fe2+ (aq) → Fe3+ (aq) + H2O (l) (in acidic solution)
(d) Cr2O7 2– + SO2(g) → Cr3+ (aq) + SO4 2– (aq) (in acidic solution)

Question 8. 19 Balance the following equations in basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.
(a) P4(s) + OH–(aq) → PH3(g) + HPO2 – (aq)
(b) N2H4(l) + ClO3 –(aq) → NO(g) + Cl–(g)
(c) Cl2O7 (g) + H2O2(aq) → ClO2 –(aq) + O2(g) + H+

Question 8. 20 What sorts of informations can you draw from the following reaction ? (CN)2(g) + 2OH–(aq) → CN–(aq) + CNO–(aq) + H2O(l)

Question 8. 21 The Mn3+ ion is unstable in solution and undergoes disproportionation to give Mn2+, MnO2, and H+ ion. Write a balanced ionic equation for the reaction.

Question 8. 22 Consider the elements :  Cs, Ne, I and F
(a) Identify the element that exhibits only negative oxidation state.
(b) Identify the element that exhibits only postive oxidation state.
(c) Identify the element that exhibits both positive and negative oxidation states.
(d) Identify the element which exhibits neither the negative nor does the positive oxidation state.

Question 8. 23 Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.

Question 8. 24 Refer to the periodic table given in your book and now answer the following questions:
(a) Select the possible non metals that can show disproportionation reaction.
(b) Select three metals that can show disproportionation reaction.

Question 8. 25 In Ostwald’s process for the manufacture of nitric acid, the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained startingonly with 10.00 g. of ammonia and 20.00 g of oxygen ?

Question 8. 26 Using the standard electrode potentials given in the Table , predict if the reaction between the following is feasible:
(a) Fe3+(aq) and I–(aq)
(b) Ag+(aq) and Cu(s)
(c) Fe3+ (aq) and Cu(s)
(d) Ag(s) and Fe3+(aq)
(e) Br2(aq) and Fe2+(aq).

Question 8. 27 Predict the products of electrolysis in each of the following:
(i) An aqueous solution of AgNO3 with silver electrodes
(ii) An aqueous solution AgNO3 with platinum electrodes
(iii) A dilute solution of H2SO4 with platinum electrodes
(iv) An aqueous solution of CuCl2 with platinum electrodes.

Question 8. 28 Arrange the following metals in the order in which they displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn.

Question 8. 29 Given the standard electrode potentials, K+/K = –2.93V, Ag+/Ag = 0.80V, Hg2+/Hg = 0.79V Mg2+/Mg = –2.37V. Cr3+/Cr = –0.74V arrange these metals in their increasing order of reducing power.

Question 8. 30 Depict the galvanic cell in which the reaction Zn(s) + 2Ag+(aq) → Zn2+(aq) +2Ag(s) takes place, Further show:
(i) which of the electrode is negatively charged,
(ii) the carriers of the current in the cell, and
(iii) individual reaction at each electrode.

Chapter 9 Hydrogen

Question 9.1 Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

Question 9.2 Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes?

Question 9.3 Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

Question 9.4 How can the production of dihydrogen, obtained from ‘coal gasification’, be increased ?

Question 9.5 Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process ?

Question 9.6 Complete the following reactions:
(i) H2 (g ) + MmOo (s)Δ→
(ii) ( ) ( ) 2 catalyst CO g + H gΔ →
(iii) ( ) ( ) 3 8 2 catalyst C H g + 3H O g Δ →
(iv) Zn(s) + NaOH(aq) heat→

Question 9.7 Discuss the consequences of high enthalpy of H–H bond in terms of chemical reactivity of dihydrogen.

Question 9.8 What do you understand by (i) electron-deficient, (ii) electron-precise, and (iii) electron-rich compounds of hydrogen? Provide justification with suitable examples.

Question 9.9 What characteristics do you expect from an electron-deficient hydride with respect to its structure and chemical reactions?

Question 9.10 Do you expect the carbon hydrides of the type (CnH2n + 2) to act as ‘Lewis’ acid or base? Justify your answer.

Question 9.11 What do you understand by the term “non-stoichiometric hydrides”? Do you expect this type of the hydrides to be formed by alkali metals? Justify your answer.

Question 9.12 How do you expect the metallic hydrides to be useful for hydrogen storage? Explain.

Question 9.13 How does the atomic hydrogen or oxy-hydrogen torch function for cutting and welding purposes ? Explain.

Question 9.14 Among NH3, H2O and HF, which would you expect to have highest magnitude of hydrogen bonding and why?

Question 9.15 Saline hydrides are known to react with water violently producing fire. Can CO2, a well known fire extinguisher, be used in this case? Explain.

Question 9.16 Arrange the following
(i) CaH2, BeH2 and TiH2 in order of increasing electrical conductance.
(ii) LiH, NaH and CsH in order of increasing ionic character.
(iii) H–H, D–D and F–F in order of increasing bond dissociation enthalpy.
(iv) NaH, MgH2 and H2O in order of increasing reducing property.

Question 9.17 Compare the structures of H2O and H2O2.

Question 9.18 What do you understand by the term ’auto-protolysis’ of water? What is its significance?

Question 9.19 Consider the reaction of water with F2 and suggest, in terms of oxidation and reduction, which species are oxidised/reduced.

Question 9.20 Complete the following chemical reactions.
(i) ( ) ( ) 2 2 PbS s + H O aq →
(ii) – ( ) ( ) 4 2 2 MnO aq + H O aq →
(iii) ( ) ( ) 2 CaO s + H O g →
(v) ( ) ( ) 3 2 AlCl g + H O l →
(vi) ( ) ( ) 3 2 2 Ca N s + H O l → Classify the above into

(a) hydrolysis,
(b) redox and
(c) hydration reactions.

Question 9.21 Describe the structure of the common form of ice.

Question 9.22 What causes the temporary and permanent hardness of water ?

Question 9.23 Discuss the principle and method of softening of hard water by synthetic ionexchange resins.

Question 9.24 Write chemical reactions to show the amphoteric nature of water.

Question 9.25 Write chemical reactions to justify that hydrogen peroxide can function as an oxidising as well as reducing agent.

Question 9.26 What is meant by ‘demineralised’ water and how can it be obtained ?

Question 9.27 Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Question 9.28 Describe the usefulness of water in biosphere and biological systems.

Question 9.29 What properties of water make it useful as a solvent? What types of compound can it (i) dissolve, and (ii) hydrolyse ?

Question 9.30 Knowing the properties of H2O and D2O, do you think that D2O can be used for drinking purposes?

Question 9.31 What is the difference between the terms ‘hydrolysis’ and ‘hydration’ ?

Question 9.32 How can saline hydrides remove traces of water from organic compounds?

Question 9.33 What do you expect the nature of hydrides is, if formed by elements of atomic numbers 15, 19, 23 and 44 with dihydrogen? Compare their behaviour towards water.

Question 9.34 Do you expect different products in solution when aluminium(III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified water, and (iii) alkaline water? Write equations wherever necessary.

Question 9.35 How does H2O2 behave as a bleaching agent?

Question 9.36 What do you understand by the terms:
(i) hydrogen economy
(ii) hydrogenation
(iii) ‘syngas’
(iv) water-gas shift reaction
(v) fuel-cell ?

(Chemistry) Chapter 10 The S -Block Elements

NCERT  Exercises Questions

Question 10.1 What are the common physical and chemical features of alkali metals ?

Question 10.2 Discuss the general characteristics and gradation in properties of alkaline earth metals.

Question 10.3 Why are alkali metals not found in nature ?

Question 10.4 Find out the oxidation state of sodium in Na2O2. 5.5 Explain why is sodium less reactive than potassium.

Question 10.6 Compare the alkali metals and alkaline earth metals with respect to (i) ionisation enthalpy (ii) basicity of oxides and (iii) solubility of hydroxides.

Question 10.7 In what ways lithium shows similarities to magnesium in its chemical behaviour?

Question 10.8 Explain why can alkali and alkaline earth metals not be obtained by chemical reduction methods?

Question 10.9 Why are potassium and caesium, rather than lithium used in photoelectric cells?

Question 10.10 When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.

Question 10.11 Beryllium and magnesium do not give colour to flame whereas other alkaline earth metals do so. Why ?

Question 10.12 Discuss the various reactions that occur in the Solvay process.

Question 10.13 Potassium carbonate cannot be prepared by Solvay process. Why ?

Question 10.14 Why is Li2CO3 decomposed at a lower temperature whereas Na2CO3 at higher temperature?

Question 10.15 Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.
(a) Nitrates
(b) Carbonates
(c) Sulphates.

Question 10.16 Starting with sodium chloride how would you proceed to prepare
(i) sodium metal
(ii) sodium hydroxide
(iii) sodium peroxide
(iv) sodium carbonate ?

Question 10.17 What happens when
(i) magnesium is burnt in air
(ii) quick lime is heated with silica
(iii) chlorine reacts with slaked lime
(iv) calcium nitrate is heated ?

Question 10.18 Describe two important uses of each of the following :
(i) caustic soda
(ii) sodium carbonate
(iii) quicklime.

Question 10.19 Draw the structure of
(i) BeCl2 (vapour)
(ii) BeCl2 (solid).

Question 10.20 The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. Explain.

Question 10.21 Describe the importance of the following :
(i) limestone
(ii) cement
(iii) plaster of paris.

Question 10.22 Why are lithium salts commonly hydrated and those of the other alkali ions usually anhydrous?

Question 10.23 Why is LiF almost insoluble in water whereas LiCl soluble not only in water but also in acetone ?

Question 10.24 Explain the significance of sodium, potassium, magnesium and calcium in biological fluids.

approx 1:10 What happens when
(i) sodium metal is dropped in water ?
(ii) sodium metal is heated in free supply of air ?
(iii) sodium peroxide dissolves in water ?

Question 10.26 Comment on each of the following observations:
(a) The mobilities of the alkali metal ions in aqueous solution are Li+ < Na+ < K+ < Rb+ < Cs+
(b) Lithium is the only alkali metal to form a nitride directly.
(c) E0 for M2+ (aq) + 2e– → M(s) (where M = Ca, Sr or Ba) is nearly constant.

Question 10.27 State as to why
(a) a solution of Na2CO3 is alkaline ?
(b) alkali metals are prepared by electrolysis of their fused chlorides ?
(c) sodium is found to be more useful than potassium ?

Question 10.28 Write balanced equations for reactions between
(a) Na2O2 and water
(b) KO2 and water
(c) Na2O and CO2.

Question 10.29 How would you explain the following observations?
(i) BeO is almost insoluble but BeSO4 in soluble in water,
(ii) BaO is soluble but BaSO4 is insoluble in water,
(iii) LiI is more soluble than KI in ethanol.

Question 10.30 Which of the alkali metal is having least melting point ?
(a) Na
(b) K
(c) Rb
(d) Cs

Question 10.31 Which one of the following alkali metals gives hydrated salts ?
(a) Li
(b) Na
(c) K
(d) Cs

Question 10.32 Which one of the alkaline earth metal carbonates is thermally the most stable ?
(a) MgCO3
(b) CaCO3
(c) SrCO3
(d) BaCO3

(Chemistry) Chapter 11 The P -Block Elements

NCERT Exercises Questions

Question 11.1 Discuss the pattern of variation in the oxidation states of (i) B to Tl and (ii) C to Pb.

Question 11.2 How can you explain higher stability of BCl3 as compared to TlCl3 ?

Question 11.3 Why does boron triflouride behave as a Lewis acid ?

Question 11.4 Consider the compounds, BCl3 and CCl4. How will they behave with water ? Justify.

Question 11.5 Is boric acid a protic acid ? Explain.

Question 11.6 Explain what happens when boric acid is heated .

Question 11.7 Describe the shapes of BF3 and BH4 –. Assign the hybridisation of boron in these species.

Question 11.8 Write reactions to justify amphoteric nature of aluminium.

Question 11.9 What are electron deficient compounds ? Are BCl3 and SiCl4 electron deficient species ? Explain.

Question 11.10 Write the resonance structures of CO3 2–and HCO3 – .

Question 11.11 What is the state of hybridisation of carbon in (a) CO3 2– (b) diamond (c) graphite?

Question 11.12 Explain the difference in properties of diamond and graphite on the basis of their structures.

Question 11.13 Rationalise the given statements and give chemical reactions : • Lead(II) chloride reacts with Cl2 to give PbCl4. • Lead(IV) chloride is highly unstable towards heat. • Lead is known not to form an iodide, PbI4.

Question 11.14 Suggest reasons why the B–F bond lengths in BF3 (130 pm) and BF4 – (143 pm) differ.

Question 11.15 If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.

Question 11.16 Aluminium trifluoride is insoluble in anhydrous HF but dissolves on addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF3 is bubbled through. Give reasons.

Question 11.17 Suggest a reason as to why CO is poisonous.

Question 11.18 How is excessive content of CO2 responsible for global warming ?

Question 11.19 Explain structures of diborane and boric acid.

Question 11.20 What happens when (a) Borax is heated strongly,
(b) Boric acid is added to water,
(c) Aluminium is treated with dilute NaOH,
(d) BF3 is reacted with ammonia ?

Question 11.21 Explain the following reactions
(a) Silicon is heated with methyl chloride at high temperature in the presence of copper;
(b) Silicon dioxide is treated with hydrogen fluoride;
(c) CO is heated with ZnO;
(d) Hydrated alumina is treated with aqueous NaOH solution.

Question 11.22 Give reasons :
(i) Conc. HNO3 can be transported in aluminium container.
(ii) A mixture of dilute NaOH and aluminium pieces is used to open drain.
(iii) Graphite is used as lubricant.
(iv) Diamond is used as an abrasive.
(v) Aluminium alloys are used to make aircraft body.
(vi) Aluminium utensils should not be kept in water overnight.
(vii) Aluminium wire is used to make transmission cables.

Question 11.23 Explain why is there a phenomenal decrease in ionization enthalpy from carbon to silicon ?

Question 11.24 How would you explain the lower atomic radius of Ga as compared to Al ?

Question 11.25 What are allotropes? Sketch the structure of two allotropes of carbon namely diamond and graphite. What is the impact of structure on physical properties of two allotropes?

Question 11.26 (a) Classify following oxides as neutral, acidic, basic or amphoteric: CO, B2O3, SiO2, CO2, Al2O3, PbO2, Tl2O3 (b) Write suitable chemical equations to show their nature.

Question 11.27 In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.

Question 11.28 When metal X is treated with sodium hydroxide, a white precipitate (A) is obtained, which is soluble in excess of NaOH to give soluble complex (B). Compound (A) is soluble in dilute HCl to form compound (C). The compound (A) when heated strongly gives (D), which is used to extract metal. Identify (X), (A), (B), (C) and (D). Write suitable equations to support their identities.

Question 11.29 What do you understand by (a) inert pair effect (b) allotropy and (c) catenation?

Question 11.30 A certain salt X, gives the following results.
(i) Its aqueous solution is alkaline to litmus.
(ii) It swells up to a glassy material Y on strong heating.
(iii) When conc. H2SO4 is added to a hot solution of X,white crystal of an acid Z separates out. Write equations for all the above reactions and identify X, Y and Z.

Question 11.31 Write balanced equations for:
(i) BF3 + LiH →
(ii) B2H6 + H2O →
(iii) NaH + B2H6 →
(iv) H3BO3→Δ
(v) Al + NaOH →
(vi) B2H6 + NH3 →

Question 11.32. Give one method for industrial preparation and one for laboratory preparation of CO and CO2 each.

Question 11.33 An aqueous solution of borax is
(a) neutral
(b) amphoteric
(c) basic
(d) acidic

Question 11.34 Boric acid is polymeric due to
(a) its acidic nature
(b) the presence of hydrogen bonds
(c) its monobasic nature
(d) its geometry

Question 11.35 The type of hybridisation of boron in diborane is
(a) sp
(b) sp2
(c) sp3
(d) dsp2

Question 11.36 Thermodynamically the most stable form of carbon i
(a) diamond
(b) graphite
(c) fullerenes
(d) coal

Question 11.37 Elements of group 14
(a) exhibit oxidation state of +4 only
(b) exhibit oxidation state of +2 and +4
(c) form M2– and M4+ ion
(d) form M2+ and M4+ ions

Question 11.38 If the starting material for the manufacture of silicones is RSiCl3, write the structure of the product formed

(Chemistry) Chapter 12 Organic Chemistry – Some Basic Principles And Techniques

NCERT Exercises Questions

Question 12.1 What are hybridisation states of each carbon atom in the following compounds ? CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6

Question 12.2 Indicate the σ and π bonds in the following molecules : C6H6, C6H12, CH2Cl2, CH2=C=CH2, CH3NO2, HCONHCH3

Question 12.3 Write bond line formulas for : Isopropyl alcohol, 2,3-Dimethyl butanal, Heptan-4- one.

Question 12.4 Give the IUPAC names of the following compounds :

Question 12.5 Which of the following represents the correct IUPAC name for the compounds concerned ?
(a) 2,2-Dimethylpentane or 2-Dimethylpentane
(b) 2,4,7- Trimethyloctane or 2,5,7-Trimethyloctane
(c) 2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane
(d) But-3-yn-1-ol or But-4-ol-1-yne.

Question 12.6 Draw formulas for the first five members of each homologous series beginning with the following compounds
(a) H–COOH
(b) CH3COCH3
(c) H–CH=CH2

Question 12.7 Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for :
(a) 2,2,4-Trimethylpentane
(b) 2-Hydroxy-1,2,3-propanetricarboxylic acid
(c) Hexanedial

Question 12.8 Identify the functional groups in the following compounds

Question 12.9 Which of the two: O2NCH2CH2O– or CH3CH2O– is expected to be more stable and why ?

Question 12.10 Explain why alkyl groups act as electron donors when attached to a π system.

Question 12.11 Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.
(a) C6H5OH
(b) C6H5NO2
(c) CH3CH=CHCHO
(d) C6H5–CHO
(e) 6 5 2 C H CH + −
(f) 3 2 CH CH CHCH + =

Question 12.12 What are electrophiles and nucleophiles ? Explain with examples.

Question 12.13 Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles :
(a) 3 3 2 CH COOH + HO– → CH COO− + H O
(b) ( ) ( )( ) 3 3 3 2 CH COCH + → CH C CN OH – CN
(c) 6 5 6 5 3 C H + → C H COCH + 3 CH CO

Question 12.14 Classify the following reactions in one of the reaction type studied in this unit.
(a) 3 2 3 2 CH CH Br + HS− → CH CH SH
(b) ( ) ( ) 3 2 2 3 2 CH C = CH + HCl → CH ClC −
(c) 3 2 2 2 2 CH CH Br + HO− → CH = CH + H O
(d) ( ) ( ) 3 3 2 3 2 2 CH C − CH OH + HBr → CH CBrCH CH

Question 12.15 What is the relationship between the members of following pairs of structures ? Are they structural or geometrical isomers or resonance contributors ?

Question 12.16 For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.

Question 12.17 Explain the terms Inductive and Electromeric effects. Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?
(a) Cl3CCOOH > Cl2CHCOOH > ClCH2COOH
(b) CH3CH2COOH > (CH3)2CHCOOH > (CH3)3C.COOH

Question 12.18 Give a brief description of the principles of the following techniques taking an example in each case.
(a) Crystallisation
(b) Distillation
(c) Chromatography

Question 12.19 Describe the method, which can be used to separate two compounds with different solubilities in a solvent S.

Question 12.20 What is the difference between distillation, distillation under reduced pressure and steam distillation ?

Question 12.21 Discuss the chemistry of Lassaigne’s test 12.22 Differentiate between the principle of estimation of nitrogen in an organic compound by (i) Dumas method and (ii) Kjeldahl’s method.

Question 12.23 Discuss the principle of estimation of halogens, sulphur and phosphorus present in an organic compound.

Question 12.24 Explain the principle of paper chromatography.

Question 12.25 Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?

Question 12.26 Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.

Question 12.27 Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.

Question 12.28 Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation ?

Question 12.29 Will CCl4 give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.

Question 12.30 Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?

Question 12.31 Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test?

Question 12.32 An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20 g of this substance is subjected to complete combustion.

Question 12.33 A sample of 0.50 g of an organic compound was treated according to Kjeldahl’s method. The ammonia evolved was absorbed in 50 ml of 0.5 M H2SO4. The residual acid required 60 mL of 0.5 M solution of NaOH for neutralisation. Find the percentage composition of nitrogen in the compound.

Question 12.34 0.3780 g of an organic chloro compound gave 0.5740 g of silver chloride in Carius estimation. Calculate the percentage of chlorine present in the compound.

Question 12.35 In the estimation of sulphur by Carius method, 0.468 g of an organic sulphur compound afforded 0.668 g of barium sulphate. Find out the percentage of sulphur in the given compound.

Question 12.36 In the organic compound CH2 = CH – CH2 – CH2 – C ≡ CH, the pair of hydridised orbitals involved in the formation of: C2 – C3 bond is:
(a) sp – sp2
(b) sp – sp3
(c) sp2 – sp3
(d) sp3 – sp3

Question 12.37 In the Lassaigne’s test for nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of:
(a) Na4[Fe(CN)6]
(b) Fe4[Fe(CN)6]3
(c) Fe2[Fe(CN)6]
(d) Fe3[Fe(CN)6]4

Question 12.38 Which of the following carbocation is most stable ?
(a) (CH3)3C. +C H2
(b) (CH3)3 +C
(c) CH3CH2 +C H2
(d) CH3 +C H CH2CH3

Question 12.39 The best and latest technique for isolation, purification and separation of organic compounds is:
(a) Crystallisation
(b) Distillation
(c) Sublimation
(d) Chromatography

Question 12.40 The reaction: CH3CH2I + KOH(aq) → CH3CH2OH + KI is classified as :
(a) electrophilic substitution
(b) nucleophilic substitution
(c) elimination
(d) addition

(Chemistry) Chapter 13 Hydrocarbons

NCERT Exercises Questions

Question 13.1 How do you account for the formation of ethane during chlorination of methane ?

Question 13.2 Write IUPAC names of the following compounds :
(a) CH3CH=C(CH3)2
(b) CH2=CH-C≡C-CH3

Question 13.3 For the following compounds, write structural formulas and IUPAC names for all possible isomers having the number of double or triple bond as indicated :
(a) C4H8 (one double bond)
(b) C5H8 (one triple bond)

Question 13.4 Write IUPAC names of the products obtained by the ozonolysis of the following compounds :
(i) Pent-2-ene
(ii) 3,4-Dimethyl-hept-3-ene
(iii) 2-Ethylbut-1-ene
(iv) 1-Phenylbut-1-ene

Question 13.5 An alkene ‘A’ on ozonolysis gives a mixture of ethanal and pentan-3- one. Write structure and IUPAC name of ‘A’.

Question 13.6 An alkene ‘A’ contains three C – C, eight C – H σ bonds and one C – C π bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of ‘A’.

Question 13.7 Propanal and pentan-3-one are the ozonolysis products of an alkene? What is the structural formula of the alkene?

Question 13.8 Write chemical equations for combustion reaction of the following hydrocarbons:
(i) Butane
(ii) Pentene
(iii) Hexyne
(iv) Toluene

Question 13.9 Draw the cis and trans structures of hex-2-ene. Which isomer will have higher b.p. and why?

Question 13.10 Why is benzene extra ordinarily stable though it contains three double bonds?

Question 13.11 What are the necessary conditions for any system to be aromatic?13.12 Explain why the following systems are not aromatic?

Question 13.13 How will you convert benzene into
(i) p-nitrobromobenzene
(ii) m- nitrochlorobenzene
(iii) p - nitrotoluene
(iv) acetophenone?

Question 13.14 In the alkane H3C – CH2 – C(CH3)2 – CH2 – CH(CH3)2, identify 1°,2°,3° carbon atoms and give the number of H atoms bonded to each one of these.

Question 13.15 What effect does branching of an alkane chain has on its boiling point?

Question 13.16 Addition of HBr to propene yields 2-bromopropane, while in the presence of benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give mechanism.

Question 13.17 Write down the products of ozonolysis of 1,2-dimethylbenzene (o-xylene). How does the result support Kekulé structure for benzene?

Question 13.18 Arrange benzene, n-hexane and ethyne in decreasing order of acidic behaviour. Also give reason for this behaviour.

Question 13.19 Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Question 13.20 How would you convert the following compounds into benzene?
(i) Ethyne
(ii) Ethene
(iii) Hexane

Question 13.21 Write structures of all the alkenes which on hydrogenation give 2-methylbutane.

Question 13.22 Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+
(a) Chlorobenzene, 2,4-dinitrochlorobenzene, p-nitrochlorobenzene
(b) Toluene, p-H3C – C6H4 – NO2, p-O2N – C6H4 – NO2. 13.23 Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

Question 13.24 Suggest the name of a Lewis acid other than anhydrous aluminium chloride which can be used during ethylation of benzene.

Question 13.25 Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms? Illustrate your answer by taking one example.

 (Chemistry) Chapter 14 Environmental Chemistry

NCERT Exercises Questions

Question 14. 1 Define environmental chemistry.

Question 14. 2 Explain tropospheric pollution in 100 words. 1

Question 14. 3 Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?

Question 14. 4 List gases which are responsible for greenhouse effect.

Question 14. 5 Statues and monuments in India are affected by acid rain. How?

Question 14. 6 What is smog? How is classical smog different from photochemical smogs?

Question 14. 7 Write down the reactions involved during the formation of photochemical smog.

Question 14. 8 What are the harmful effects of photochemical smog and how can they be controlled?

Question 14. 9 What are the reactions involved for ozone layer depletion in the stratosphere?

Question 14. 10 What do you mean by ozone hole? What are its consequences?

Question 14. 11 What are the major causes of water pollution? Explain.

Question 14. 12 Have you ever observed any water pollution in your area? What measures would you suggest to control it?

Question 14. 13 What do you mean by Biochemical Oxygen Demand (BOD)?

Question 14. 14 Do you observe any soil pollution in your neighbourhood? What efforts will you make for controlling the soil pollution?

Question 14. 15 What are pesticides and herbicides? Explain giving examples.

Question 14. 16 What do you mean by green chemistry? How will it help decrease environmental pollution?

Question 14. 17 What would have happened if the greenhouse gases were totally missing in the earth’s atmosphere? Discuss. 1

Question 14.18 A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

Question 14. 19 How can domestic waste be used as manure?

Question 14. 20 For your agricultural field or garden you have developed a compost producing pit. Discuss the process in the light of bad odour, flies and recycling of wastes for a good produce.

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(Date Sheet) CBSE : Class 12th Board Examination - 2017

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