Q.Aluminium is extracted from alumina by electrolysis of a molten mixture of

Aluminium is extracted by electrolysing purified Al2O3 dissolved in molten cryolite (Na3AlF6) with CaF2 added as a flux (Hall-Héroult process).

Pure alumina (Al2O3) has a very high melting point (~2050degC), so electrolysing it alone would be extremely energy-intensive. In the Hall-Héroult process, purified Al2O3 is dissolved in molten cryolite (Na3AlF6), which lowers the melting point of the mixture to about 950degC and also increases its electrical conductivity. Calcium fluoride (CaF2) is added as a flux to further lower the melting point and improve conductivity. Electrolysis of this molten mixture (in a carbon-lined cell, carbon anode and cathode) deposits molten aluminium at the cathode: …