(a) Distinguish between ionic and covalent compounds under the following properties:
(i) Strength of forces between constituent elements
(ii) Solubility of compounds in water
(iii) Electrical conduction in substances
(b) Explain how the following metals are obtained from their compounds by the reduction process:
(i) Metal M which is in the middle of the reactivity series.
(ii) Metal N which is high up in the reactivity series.
Give one example of each type
OR
(a) Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
(b) Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines.
(c) Name the anode, the cathode and the electrolyte used in the electrolytic refining of impure copper
Answers
A)
1)ionic compound has a very strong inter-ionic forces whereas covalent compounds have comparitively weaker attractive forces between the constituent elements.
2)ionic compounds are soluble in polar solvents such as water but insoluble in polar solvents such as petrol, kerosene etc. whereas covalent compounds are soluble in petrol and kerosene and insoluble in water.
3)ionic compounds conduct electricity in molten form but covalent compounds do not conduct electricity as they do not dissociate into water
B)
metal m will be obtain by the process of calcination or roasting depending upon its ore
( calcination- if its carbonate ore is present ,
roasting -if it's sulphide ore is present ) after the above process metal oxide will form which
will then reduced to pure metal. for eg - zinc
metal N would be obtained by its electrolitic refining. for eg - sodium