Estimate the minimum potential difference needed to reduce Al2O3 at 500o C. The free energy change for the decomposition reaction: 2/3 Al2O3→4/3 Al + O2 is ∆G= +960 kJ Share with your friends Share 56 Geetha answered this 23 Al2O3→43 Al + O2 is ∆G= +960 kJ∆G = -nFE0 960 × 103 = 3×43 × 96500 × E0 ( the Al changes from +3 to 0 oxidation state, so 3 electrons are involvefor 1 Al. Therefore for 4/3 Al we need 43 × 3 =4 electrons)E0 = 960 × 1034 × 96500 = 2.487 V 285 View Full Answer