Chapter 3

Metals and Non-metals

āϧাāϤু āφ⧰ু āĻ…-āϧাāϤু


EXERCISES

āĻŦ্āϝাāϝ়াāĻŽ

 1. Which of the following pairs will give displacement znreactions?

 ā§§. āύিāĻŽ্āύāϞিāĻ–িāϤ āĻ•োāύāϝোā§°ে āϏ্āĻĨাāύāϚ্āϝুāϤি ā§°āĻ–াā§° āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়া āĻĒ্ā§°āĻĻাāύ āϕ⧰িāĻŦ?

 (a) NaCl solution and copper metal 

(āĻ•) āĻāύāĻāϚিāĻāϞ āĻĻ্ā§°ā§ąāĻŖ āφ⧰ু āϤাāĻŽāϧাāϤু

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 (b) MgCl, solution and aluminium metal

 (āĻ–) āĻāĻŽāϜিāϚিāĻāϞ, āĻĻ্ā§°ā§ąāĻŖ āφ⧰ু āĻāϞুāĻŽিāύিāϝ়াāĻŽ āϧাāϤু

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(c) FeSO, solution and silver metal 

(āĻ—) āĻĢেāϚো, āĻĻ্ā§°ā§ąāĻŖ āφ⧰ু ā§°ূāĻĒাāϞী āϧাāϤু 

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(d) AgNO, solution and copper metal.

(āϘ) āĻāϜিāĻāύāĻ…', āĻĻ্ā§°ā§ąāĻŖ āφ⧰ু āϤাāĻŽāϧাāϤু।

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2. Which of the following methods is suitable for preventing an iron frying pan from rusting?

⧍. āϞো āĻĢ্ā§°াāχং āĻĒেāύ āĻāϟাāĻŽাāĻŽā§°া āĻĒ্ā§°āϤিāĻšāϤ āϕ⧰াā§° āĻŦাāĻŦে āύিāĻŽ্āύāϞিāĻ–িāϤ āĻ•োāύāϟো āĻĒāĻĻ্āϧāϤি āωāĻĒāϝুāĻ•্āϤ?

 (a) Applying grease

 (āĻ•) āĻ—্ā§°ীāϜ āĻĒ্ā§°āϝ়োāĻ— āϕ⧰া

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(b) Applying paint

(āĻ–) ā§°ং āĻĒ্ā§°āϝ়োāĻ— āϕ⧰া

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(c) Applying a coating of zinc

(āĻ—) āϜিংāϕ⧰ āĻ†ā§ąā§°āĻŖ āĻĒ্ā§°āϝ়োāĻ— āϕ⧰া

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(d) All of the above.

(āϘ) āĻ“āĻĒā§°োāĻ•্āϤ āϏāĻ•āϞোāĻŦোā§°।

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3. An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be

 ā§Š. āĻāϟা āωāĻĒাāĻĻাāύে āĻ…āĻ•্āϏিāϜেāύ⧰ āϏৈāϤে āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়া āϕ⧰ি āωāϚ্āϚ āĻ—āϞāύ āĻŦিāύ্āĻĻুāĻĨāĻ•া āϝৌāĻ— āĻāϟা āĻĒ্ā§°āĻĻাāύ āϕ⧰ে। āĻāχ āϝৌāĻ—āϟো āĻĒাāύীāϤ āĻĻ্ā§°ā§ąāĻŖীāϝ়। āωāĻĒাāĻĻাāύāϟো āĻšোā§ąাā§° āϏāĻŽ্āĻ­াā§ąāύা āφāĻ›ে


(a) calcium

(āĻ•) āĻ•েāϞāϚিāϝ়াāĻŽ

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(b) carbon

(āĻ–) āĻ•াā§°্āĻŦāύ

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(c) silicon

(āĻ—) āϚিāϞিāĻ•āύ

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(d) iron.

(āϘ) āϞো।

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4. Food cans are coated with tin and not with zinc because 

ā§Ē. āĻ–াāĻĻ্āϝ⧰ āĻ•েāύāĻŦোā§° āϟিāύেā§°ে āĻĒ্ā§°āϞেāĻĒ āĻĻিāϝ়া āĻšāϝ় āφ⧰ু āϜিংāϕ⧰ āϏৈāϤে āύāĻšāϝ় āĻ•িāϝ়āύো 

(a) zinc is costlier than tin.

(āĻ•) āϜিংāĻ• āϟিāύāϤāĻ•ৈ āĻŦ্āϝāϝ়āĻŦāĻšুāϞ।

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(b) zinc has a higher melting point than tin.

(āĻ–) āϜিংāϕ⧰ āϟিāύāϤāĻ•ৈ āĻ…āϧিāĻ• āĻ—āϞāύ āĻŦিāύ্āĻĻু āĻĨাāĻ•ে।

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(c) zinc is more reactive than tin. 

(āĻ—) āϜিংāĻ• āϟিāύāϤāĻ•ৈ āĻ…āϧিāĻ• āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়াāĻļীāϞ। 

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(d) zinc is less reactive than tin.

(āϘ) āϜিংāĻ• āϟিāύāϤāĻ•ৈ āĻ•āĻŽ āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়াāĻļীāϞ।

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5. You are given a hammer, a battery, a bulb, wires and a switch.

ā§Ģ. āφāĻĒোāύাāĻ• āĻāϟা āĻšাāϤুā§°ী, āĻŦেāϟাā§°ী, āĻāϟা āĻŦাāϞ্āĻŦ, āϤাঁā§° āφ⧰ু āĻāϟা āϚুāχāϚ āĻĻিāϝ়া āĻšৈāĻ›ে।

 (a) How could you use them to distinguish between samples of metals and non-metals?

 (āĻ•) āϧাāϤু āφ⧰ু āĻ…-āϧাāϤুā§° āύāĻŽুāύাā§° āĻŽাāϜāϤ āĻĒাā§°্āĻĨāĻ•্āϝ āϕ⧰িāĻŦāϞৈ āφāĻĒুāύি āϏেāχāĻŦোā§° āĻ•েāύেāĻĻā§°ে āĻŦ্āĻ¯ā§ąāĻšাā§° āϕ⧰িāĻŦ āĻĒাā§°ে?

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(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.

(āĻ–) āϧাāϤু āφ⧰ু āĻ…-āϧাāϤুā§° āĻŽাāϜāϤ āĻĒাā§°্āĻĨāĻ•্āϝ āϕ⧰াāϤ āĻāχ āĻĒā§°ীāĻ•্āώাāĻŦোā§°ā§° āωāĻĒāϝোāĻ—িāϤা āĻŽূāϞ্āϝাāϝ়āύ āϕ⧰āĻ•।

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 6. What are amphoteric oxides? Give two examples of amphoteric oxides.

 ā§Ŧ. āĻāĻŽ্āĻĢোāϟেā§°িāĻ• āĻ…āĻ•্āϏাāχāĻĄ āĻ•ি? āĻāĻŽ্āĻĢোāϟেā§°িāĻ• āĻ…āĻ•্āϏাāχāĻĄā§° āĻĻুāϟা āωāĻĻাāĻšā§°āĻŖ āĻĻিāϝ়āĻ•।

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7. Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

ā§­. āĻĒাāϤāϞ āĻāϚিāĻĄā§° āĻĒā§°া āĻšাāχāĻĄ্ā§°āϜেāύ āϏ্āĻĨাāύāϚ্āϝুāϤ āϕ⧰িāĻŦ āĻĒā§°া āĻĻুāϟা āϧাāϤুā§° āύাāĻŽ āĻĻিāϝ়āĻ•, āφ⧰ু āĻĻুāϟা āϧাāϤু āϝি āύāϕ⧰ে।

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8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

ā§Ž. āϧাāϤু āĻāĻŽ-ā§° āĻŦৈāĻĻ্āϝুāϤিāĻ• āĻļোāϧāύāϤ, āφāĻĒুāύি āĻāύোāĻĄ, āĻ•েāĻĨ'āĻĄ āφ⧰ু āχāϞেāĻ•্āϟ্ā§°āϞাāχāϟ āĻšিāϚাāĻĒে āĻ•ি āϞ'āĻŦ?

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9. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.

⧝. āĻĒ্ā§°āϤ্āϝুāώে āĻāϟা āϏ্āĻĒাāϚুāϞাāϤ āĻ›াāϞāĻĢাā§° āĻĒাāωāĻĄাā§° āϞৈ āĻ—ā§°āĻŽ āϕ⧰িāϞে। āϤেāĻ“ঁ āχāϝ়াā§° āĻ“āĻĒā§°āϤ āĻāϟা āĻĒā§°ীāĻ•্āώা āύāϞী āĻ“āϞোāϟাāχ āĻŦিāĻ•āĻļিāϤ āĻšোā§ąা āĻ—েāĻ›āϟো āϏংāĻ—্ā§°āĻš āϕ⧰িāĻ›িāϞ, āϤāϞ⧰ āϚিāϤ্ā§°āϤ āĻĻেāĻ–ুāĻ“ā§ąাā§° āĻĻā§°ে।

(a) What will be the action of gas on

(āĻ•) āĻ—েāϛ⧰ āĻ•াā§°্āϝ āĻ•ি āĻš'āĻŦ

                (i) dry   litmus paper? 

                (āĻ•) āĻĄ্ā§°াāχ āϞিāϟāĻŽাāĻ› āĻ•াāĻ—āϜ?

                (ii) moist litmus paper?

               (āĻ–) āφ⧰্āĻĻ্ā§° āϞিāϟāĻŽাāĻ› āĻ•াāĻ—āϜ?

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(b) Write a balanced chemical equation for the reaction taking place.

(āĻ–) āĻšোā§ąা āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়াā§° āĻŦাāĻŦে āĻāĻ• āϏāύ্āϤুāϞিāϤ ā§°াāϏাāϝ়āύিāĻ• āϏāĻŽীāϕ⧰āĻŖ āϞিāĻ–āĻ•।

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 10. State two ways to prevent the rusting of iron.

 ā§§ā§Ļ. āϞোā§° āĻŽাāĻŽā§° āĻĒ্ā§°āϤিā§°োāϧ āϕ⧰াā§° āĻĻুāϟা āωāĻĒাāϝ় āωāϞ্āϞেāĻ– āϕ⧰āĻ•।

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11. What type of oxides are formed when non-metals combine with oxygen?

ā§§ā§§. āĻ…-āϧাāϤুāĻŦোā§° āĻ…āĻ•্āϏিāϜেāύ⧰ āϏৈāϤে āĻŽিāĻšāϞি āĻš'āϞে āĻ•েāύে āϧ⧰āĻŖā§° āĻ…āĻ•্āϏাāχāĻĄ āϏৃāώ্āϟি āĻšāϝ়?

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12. Give reasons.

⧧⧍. āĻ•াā§°āĻŖ āĻĻিāϝ়āĻ•।

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(a) Platinum, gold and silver are used to make jewellery.

(āĻ•) āĻ—āĻšāύা āϤৈāϝ়াā§° āϕ⧰িāĻŦāϞৈ āĻĒ্āϞেāϟিāύাāĻŽ, āϏোāĻŖ āφ⧰ু ā§°ূāĻĒ āĻŦ্āĻ¯ā§ąāĻšাā§° āϕ⧰া āĻšāϝ়।

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(b) Sodium, potassium and lithium are stored under oil.

(āĻ–) āĻ›āĻĄিāϝ়াāĻŽ, āĻĒāϟাāĻ›িāϝ়াāĻŽ āφ⧰ু āϞিāĻĨিāϝ়াāĻŽ āϤেāϞ⧰ āϤāϞāϤ āϏংā§°āĻ•্āώāĻŖ āϕ⧰া āĻšāϝ়।

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 (c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.

 (āĻ—) āĻāϞুāĻŽিāύিāϝ়াāĻŽ āĻšৈāĻ›ে āĻāĻ• āĻ…āϤ্āϝাāϧিāĻ• āĻĒ্ā§°āϤিāĻ•্ā§°িāϝ়াāĻļীāϞ āϧাāϤু, āϤāĻĨাāĻĒিāĻ“ āχāϝ়াāĻ• ā§°āύ্āϧাā§° āĻŦাāĻŦে āĻŦাāϚāύ-āĻŦā§°্āϤāύ āϤৈāϝ়াā§° āϕ⧰িāĻŦāϞৈ āĻŦ্āĻ¯ā§ąāĻšাā§° āϕ⧰া āĻšāϝ়।

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(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

(āϘ) āύিāώ্āĻ•াāĻļāύ āĻĒ্ā§°āĻ•্ā§°িāϝ়াā§° āϏāĻŽāϝ়āϤ āĻ•াā§°্āĻŦোāύেāϟ āφ⧰ু āĻ›াāϞāĻĢাāχāĻĄ āĻ…'ā§°āĻŦোā§° āϏাāϧাā§°āĻŖāϤে āĻ…āĻ•্āϏাāχāĻĄāϞৈ ā§°ূāĻĒাāύ্āϤ⧰িāϤ āĻšāϝ়।

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13. You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

ā§§ā§Š. āφāĻĒুāύি āύিāĻļ্āϚāϝ় āύেāĻŽু āĻŦা āϤাāĻŽোāϞ⧰ ā§°āϏেā§°ে āĻ•āϞāĻ™্āĻ•িāϤ āϤাāĻŽā§° āĻĒাāϤ্ā§°āĻŦোā§° āĻĒā§°িāώ্āĻ•াā§° āϕ⧰া āĻĻেāĻ–িāĻ›ে। āĻāχ āϟেāĻ™া āĻĒāĻĻাā§°্āĻĨāĻŦোā§° āĻ•িāϝ় āĻĒাāϤ্ā§°āĻŦোā§° āĻĒā§°িāώ্āĻ•াā§° āϕ⧰াāϤ āĻ•াā§°্āϝāϕ⧰ী āĻšāϝ় āĻŦā§°্āĻŖāύা āϕ⧰āĻ•।

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14. Differentiate between metal and non-metal on the basis of their chemical properties.

ā§§ā§Ē. āϧাāϤু āφ⧰ু āĻ…-āϧাāϤুā§° āĻŽাāϜāϤ āϤেāĻ“ঁāϞোāϕ⧰ ā§°াāϏাāϝ়āύিāĻ• āĻ—ুāĻŖাāĻ—ুāĻŖā§° āĻ“āĻĒā§°āϤ āφāϧাā§°িāϤ āϕ⧰ি āĻĒাā§°্āĻĨāĻ•্āϝ āϕ⧰āĻ•।

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15. A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

ā§§ā§Ģ. āĻāϜāύ āĻŦ্āϝāĻ•্āϤিāϝ়ে āϘ⧰ে āϘ⧰ে āĻ—ৈ āϏোāĻŖোā§ąাāϞ ā§°āĻ–াā§° āĻĻā§°ে āĻĒোāϜ āĻĻিāĻ›িāϞ। āϤেāĻ“ঁ āĻĒুā§°āĻŖি āφ⧰ু āύিāϏ্āϤেāϜ āϏোāĻŖā§° āĻ…āϞংāĻ•াā§°ā§° āϜিāϞিāĻ•ি āϘূā§°াāχ āĻ…āύাā§° āĻĒ্ā§°āϤিāĻļ্ā§°ুāϤি āĻĻিāĻ›িāϞ। āĻāĻ—ā§°াāĻ•ী āĻ…āϏāύ্āĻĻিāĻ—্āϧ āĻŽāĻšিāϞাāχ āϤেāĻ“ঁāĻ• āϏোāĻŖā§° āϚুāĻĄ়িā§° āĻāϟা āĻ›েāϟ āĻĻিāĻ›িāϞ āϝিāϟো āϤেāĻ“ঁ āĻāϟা āύিā§°্āĻĻিāώ্āϟ āϏāĻŽাāϧাāύāϤ āĻĄুāĻŦাāχ āĻ›িāϞ। āϚুāĻĄ়িāĻŦোā§° āύāϤুāύ⧰ āĻĻā§°ে āϜিāϞিāĻ•ি āωāĻ িāĻ›িāϞ āĻ•িāύ্āϤু āϏিāĻšঁāϤ⧰ āĻ“āϜāύ āϝāĻĨেāώ্āϟ āĻš্ā§°াāϏ āĻĒাāχāĻ›িāϞ। āĻŽāĻšিāϞাāĻ—ā§°াāĻ•ী āĻŦিāϚāϞিāϤ āĻšৈāĻ›িāϞ āĻ•িāύ্āϤু āĻāĻ• āύিāώ্āĻĢāϞ āϤ⧰্āϕ⧰ āĻĒিāĻ›āϤ āĻŽাāύুāĻšāϜāύে āĻ–ā§°āĻ–েāĻĻাāĻ•ৈ āĻĒāĻļ্āϚাāĻĻāĻĒāϏ⧰āĻŖ āϕ⧰িāĻ›িāϞ। āϤেāĻ“ঁ āĻŦ্āĻ¯ā§ąāĻšাā§° āϕ⧰া āϏāĻŽাāϧাāύ⧰ āĻĒ্ā§°āĻ•ৃāϤি āϜাāύিāĻŦāϞৈ āφāĻĒুāύি āĻĄিāϟেāĻ•āϟিāĻ­ā§° āĻ­ূāĻŽিāĻ•া āĻĒাāϞāύ āϕ⧰িāĻŦ āĻĒাā§°িāĻŦāύে?

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ā§§ā§Ŧ. Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).

16. āϤীāĻ–া āύāĻšāϝ় āĻ—ā§°āĻŽ āĻĒাāύীā§° āϟেংāĻ• āϤৈāϝ়াā§° āϕ⧰িāĻŦāϞৈ āϤাāĻŽ āĻ•িāϝ় āĻŦ্āĻ¯ā§ąāĻšাā§° āϕ⧰া āĻšāϝ় āϤাā§° āĻ•াā§°āĻŖ āĻĻিāϝ়āĻ• (āϞোā§° āĻŽিāĻļ্ā§°āĻŖ)।

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 Question Type Jit Bora.