In the extraction of aluminium by Hall-Heroult process, purified Al2O3 is mixed with CaF2 to
In the extraction of aluminium by Hall-Heroult process, purified Al2O3 is mixed with CaF2 to

(i) lower the melting point of Al2O3

(ii) increase the conductivity of molten mixture.

(iii) reduce Al3+ into Al(s).

(iv) acts as a catalyst

 

Correct Answers:

(i) lower the melting point of Al2O3

(ii) increase the conductivity of molten mixture.

Explanation: In the extraction of aluminium by Hall-Heroult process, purified Al2O3 is mixed with CaF2 to lower the melting point of Al2O3 and to increase the conductivity of molten mixture.