The major role of fluorpar (`CaF_2` ) which added in small quantities in the electrolyte reduction of alumina dissolved in fused cryolite `(N_(3)AlF_(6)` ) is

Options

A. as a catalyst
B. to make the fused mixture very conducting to lower the temperature of the melt
C. to lower the temperature of the melt
D. to decrease the rate of oxidation of carbon at anode.

Answer

B, C

Explanation

Fluorspar when added to alumina and cryolite make the fused mixture very conducting and reduce the melting point of the mixture.