Question

The role of fluorspar $\left(Ca{F}_2\right)$ which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite $\left(N{a}_{3}Al{F}_6\right)$ is:

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

Answer 1

The correct option is B

to make the fused mixture very conducting

The conductivity of the electrolyte which is a mixture of Alumina, cryolite and fluorospar increases by addition of a small amount of $\left(Ca{F}_2\right)$ due to its high ionic nature.