Q.
The. free energy change for the decomposition reaction, 32Al2O334Al+O2 is ΔG=+960kJ ( F=96500Cmol−1 ) The minimum potential difference required to reduce Al2O3 at 500∘C will be
Al2O3(2Al3++3O2−)2Al+23O2;n=6e−32Al2O334Al+O2;n=4e−ΔG=+960kJ=+960000JΔG=−nFE960000=−4×96500×EE=−2.487V Minimum potential difference required to reduce Al2O3 is 2.487 V.