Question

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

• A. the three layers have same densities but different matrials
• B. the three layers have different densities
• 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 $Ba{F}_2$

Answer 1

Answer: (B), (C), (D)

The correct options are
B the three layers have different densities
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 $Ba{F}_2$

In the Hoop's process of aluminium purification, upper most layer is of pure molten aluminium, middle layer is of molten fluorides of $N{a}^{+},B{a}^{+2}$ and $A{l}^{+3}$ and lower layer is of molten impure aluminium have different densities.