Commercially, aluminium is obtained from purified aluminium oxide by

Options

A. electrolysis of aqueous `Al_2(SO_4)_3`
B. electrolysis of aqueous `KAI(SO_4)_2`
C. electrolysis of a fused mixture of `Al_2 O_3` and `Na_3AlF_6`
D. reduction with coke at high temperatures

Answer

C

Explanation

Aluminium is obtained by electrolytic reduction of purified alumina mixed with cryolite `(Na_2 AIF_6)` and fluorspar `(CaF_2)` in an iron tank with carbon lining. The process is called Hall-Heroult process.