Question

In the electrolytic reduction of pure alumina to pure aluminium – by Hall Herault’s process, give the electrolytic reactions involved in the same, resulting in formation of aluminium at the cathode.

Answer 1

Aluminium is obtained from alumina (Al₂O₃ ) by electrolytic reduction. The electrolytic both consists of a mixture of cryolite (Na₃AlF₆ ) and fluorspar (CaF₂ ) and alumina (Al₂O₃).

The O₂ so produced reacts with carbon of the anode to give CO. 

2C +O₂ →2CO