In Hall – Heroult process, the following is used for reducing Al2O3 : (A) CaF2 (B) Na3AlF6 (C) Graph — JEE Mains Chemistry Past Papers Chemistry Question

💡 Solution & Explanation

Electrolytic reduction (Hall-Heroult process) : The purified Al2O3 is mixed with Na3AlF6 (cryolite) or CaF2 (fluorspar) which lowers the melting point of the mixture and brings conductivity. The fused matrix is electrolysed. Steel cathode and graphite anode are used. The graphite anode is useful here for reduction to the metal. The overall reaction may be taken as : 2Al2O3 + 3C  4Al + 3CO2 The electolysis of the molten mass is carried out in an electrolytic cell using carbon electrodes. In hall Heroult process graphite is act as reducing agent