QUESTIONS FROM CBSE EXAMINATION PAPERS
I. VERY SHORT ANSWER QUESTIONS (1 Mark)
1. Why do silver ornaments loose their shine when kept for some time? [2010 (T-1)]
2. Name a metal other than aluminium that is covered with an oxide film layer. [2010 (T-1)]
3. Name one metal and one non-metal which exists in liquid state at room temperature? [2010 (T-1)]
4. Name a non-metal which is lustrous and a metal which is non-lustrous. [2010 (T-1)]
5. Name two metals which have very low melting point. [2010 (T-1)]
6. If copper metal is heated over a flame, it develops a coating. What is the colour and composition of this coating? [2010 (T-1)]
7. Why is sodium metal kept immersed in kerosene oil? [2010 (T-1)]
8. Name one metal which react with very dilute HNO3 to evolve hydrogen gas. [2010 (T-1)]
9. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y, and Z. [2010 (T-1)]
10. An element A form two oxides AO and AO2. The oxide AO is neutral whereas the oxide AO2 is acidic in nature. Would you call element A a metal or non-metal. [2010 (T-1)]
II. SHORT ANSWER QUESTIONS (2/3 Marks)
11. What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires? [HOTS]
12. What happen when (a) ZnCO3 is heated in the absence of oxygen? (b) a mixture of Cu2O and Cu2S is heated?[HOTS]
13. A metal P is placed in an aqueous solution of Q. In a few hours metal Q was deposited on metal P. Which metal amongst P and Q is more reactive and why? [HOTS]
14. State reasons for the following observations:
(i) The shining surface of some metals becomes dull when exposed to air for a long time.
(ii) Metals sulphides occur mainly in rocks but metal halides occur mostly in sea and lake. [2009]
15. Differentiate between roasting and calcinations processes used in metallurgy. Give an example of each. [2008]
16. Give reason for the following:
(a) Gold and silver are used to make jewellery.
(b) Carbonate and sulphide ores are usually converted into oxides prior to reduction during the process of extraction. [2008]
17. Compound X and aluminium are used to join railway tracks. [HOTS]
(a) Identity the compound X (b) Name the reaction (c) Write down its reaction.
18. Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores. [HOTS]
19. (a) What type of reaction is to be performed to ascertain and verify the position of metals in the reactivity series?
(b) If an iron nail immersed in the aqueous solution of copper sulphate, what are the changes happening to the nail and to the solution?
(c) Write the balanced chemical equation for the reaction between iron metal and aqueous copper sulphate solution. [2010 (T-1)]
20. Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction? [2008]
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