Hoop's process of purification of aluminium involves formation of layers during electrolysis. It involves:

Options

A. the three layers have same density but different materials.
B. the three layers have different desities.
C. the upper layer is of pure aluminium which acts as a cathode.
D. the bottom layer is of impure aluminium which acts as an anode and middle layer consists of cryolite and `BaF_(2)`.

Answer

B,C,D