36. Aluminium is extracted from alumina (Al2O3
) by electrolysis of a molten mixture of :
(1) Al2O3
+ KF + Na3AlF6
(2) Al2O3
+ HF + NaAlF4
(3) Al2O3
+ CaF2
+ NaAlF4
(4) Al2O3
+ Na3AlF6
+ CaF2
) by electrolysis of a molten mixture of :
(1) Al2O3
+ KF + Na3AlF6
(2) Al2O3
+ HF + NaAlF4
(3) Al2O3
+ CaF2
+ NaAlF4
(4) Al2O3
+ Na3AlF6
+ CaF2