The minimum voltage required to electrolyse alumina in the Hall-Heroult process is [Given, ΔGo(Al2O3)=−1520 kJ/mol and ΔGo(CO2)=−394 kJ/mol]

In Hall-Heroult process the following reactions occur 3C+2Al2O3→4Al+3CO2ΔGo=3ΔfGo(CO2)−2ΔfGo(Al2O3)=3(−394)−2(−1520)=1858 kJΔGo=−nFEo=or=−Eo=ΔGonF=1858×100012×96500=1.60 V