Incorrect statement in electrolysis of `Al_(2)O_(3)` by Hall-Heroult process is :

Options

A. Cryolite `N_(3)[AlF_(5)]` lowers the m.pt. of `Al_(2)O_(3)` and increases its electrical conductivity
B. Al is obtained at cathode and `CO_(2)` at anode
C. `Li_(2)CO_(3)` can be used in place of cryolite `(Na_(3)AlF_(6))`
D. `MgF_(2)` can be used in place of flourspare `(CaF_(2))`

Answer

D

Explanation

`Mg^(2+)` cation will be preferentially discharge than `Al^(3+)` at cathode.