(a) Give the chemical names and formulae of the main ores of

(i) aluminium,

(ii) iron and

(iii) zinc.

(b) Which impurities are present in bauxite?

(c) What is red mud, how is it removed?

Distinguish between electrolytic methods of reduction and refining.

(a) Aluminium is a more active metal than iron but suffers less corrosion. Why?

(b) Explain and give reasons why aluminium vessels should not be cleaned with powders containing alkalis.

Explain with reasons:

In the electrolytic reduction of alumina, the graphite anode is gradually consumed.

or

Why the anode has to be replaced from time to time in this process?