Question

Give reasons:
(i) Name the method of refining of nickel.
(ii) What is the role of cryolite in the extraction of aluminium?
(iii) What is the role of limestone in the extraction of iron from its oxides?

Answer 1

(i) Mond process.

(ii) 1. Cryolite lowers the melting point of alumina from 2323K to 1410K.

2. It functions as a solvent for alumina.

3. The melt of alumina and cryolite conducts electricity.

(iii) Limestone (containing calcium carbonate) is added to get rid of the sandy bits of rock in the ore, which are acidic. The limestone is broken down in the hot furnace.