Q1. Why Sodium forms Sodium Hydroxide when reacting with water whereas Aluminium forms only Aluminium Oxide?
Q2. What happens when:
(i) ZnCO3 is heated in the absence of oxygen?
(ii) a mixture of Cu2O and Cu2S is heated?
Q3. Why the reduction process is always involved in the extraction of metals?
Q4. State the property utilised in the following:
(i) Graphite in making electrodes.
(ii) Electrical wires are coated with Polyvinyl Chloride (PVC) or a rubber-like material.
(iii) Metal alloys are used for making bells and strings of musical instruments.
Q5. A, B and C are 3 elements which undergo chemical reactions according to the following equations:
(a) A2O3 + 2B → B2O3+ 2A
(b) 3CSO4 + 2B → B2 (SO4)3 + 3C
(c) 3CO + 2A → A2O3+ 3C
Answer the following questions:
(i) Which element is most reactive?
(ii) Which element is least reactive?
(iii) State the type of reaction listed above.
Q6. Compound P and aluminium are used to join railway tracks.
(i) Identify the compound P.
(ii) Name the reaction.
(iii) Write the equation for it.
Q7. An ore on heating in air produces Sulphur Dioxide.
(i) Which process would you suggest for its concentration?
(ii) Describe briefly any two steps involved in the conversion of this concentrated ore into related metal.
Q8. State reason for the following:
(i) Non-metals cannot displace hydrogen from the acids.
(ii) Hydrogen is not a metal, yet it is placed in the activity series of metals.
(iii) Aluminium is more reactive than iron, yet its corrosion is less than that of iron.
Q9. (a) List in tabular form any three chemical properties on the basis of which metals and non-metals are differentiated.
(b) State two ways to prevent the rusting of iron.
Q10. Define alloys. List the properties of alloys that make them useful over pure metals? Explain this fact with suitable examples.
Q11. What is cinnabar? How is a metal extracted from cinnabar? Explain briefly.
Q12.Giving one example of each. Explain the method of obtaining the following metals from their compounds.
Metal ‘X’, which is low in the activity series.
Metal ‘Y’, which is in the middle in the activity series.
Metal ‘Z’, which is towards the top of the activity series.
Q13. Write chemical equations for reactions taking place when
(a) Manganese Dioxide is heated with aluminium powder.
(b) Steam is passed over hot iron.
(c) Magnesium is treated with dil.HNO3 .
Q14. Give reasons for the following:
(a) Metals are regarded as electropositive elements.
(b) When a piece of copper metal is added to a solution of zinc sulphate, no change takes place but the blue colour of copper sulphate fades away when a piece of zinc is placed in its solution.
(c) Articles made of aluminium do not corrode even though aluminium is an active metal.
Q15. What is corrosion of metals? Name one metal which does not corrode and one which corrodes on being kept in open atmosphere.
Q16. Zn is more electropositive than Fe. Therefore, it should get corroded faster than Fe. But it does not happen. Instead, it is used to galvanise Iron. Explain why?
Q17. Why Al metal cannot be obtained by the reduction of Al2O3 with coke? Explain.
Q18. List three properties of sodium in which it differs from the general physical properties of most of the metals.