During Hoope's process for eelctrolytic refining of Al, the middle layer is of

Options

A. Pure aluminium
B. Impure aluminium
C. Cryolite and `BaF_(2)`
D. Alloys to Al, Ca, Si

Answer

C

Explanation

Cryolite `+BaF_(2)`. Middle layer consists of fused mixture of fluorides of Ba, Al and Na.