Question

In the electrolytic refining for aluminium extraction the electrolyte used is:

• A. fluorides of $Al,Na$ and $Ca$
• B. $Al(OH{)}_3$ in $NaOH$ solution
• C. an aqueous solution of $A{l}_2(S{O}_4{)}_3$
• D. molten $A{l}_2{O}_3$

Answer 1

The correct option is A fluorides of $Al,Na$ and $Ca$

In the extraction of aluminium by electrolytic process alumina $A{l}_2{O}_3$ is used along with fluorspar $Ca{F}_2$ and cryolite.
Cryolite reduces the melting temp. of the mixture and also act as solvent and helps dissolve $A{l}_2{O}_3$.
So, fluorides of $Al,Na$ and $Ca$ are used as electrolyte.