Aluminium is extracted by the electrolysis of

Aluminium can be extracted by electrolyzing the purified 2 3 Al O . This 2 3 Al O is mixed with either 3 6 Na AlF or 2 CaF . 3 6 Na AlF or 2 CaF are cryolites, these are added to lower the melting point of the mixture and to bring the conductivity. This is a well-known electrolysis and is known as the Hall- Heroult process. The reaction is 2 3 2 Al O +3C 4Al+3CO -> 98. Fused cryolite is used in the electrolytic extraction of aluminium: (a) To decomposes alumina (b) To oxidise alumina (c) To protect anode (d) To protect cathode Alumina whose formula is 2 3 Al O and it is used along the c