nE1∘+nE2∘=nE3∘ [n= number of electron transferred ] E1∘+2E2∘=3E3∘ EFe3+/Fe2+0+2EFe2+/Fe(s)0=3EFe3+/Fe(s)0 EFe3+/Fe2+∘+(−0.440)×2=(−0.036)×3 EFe3+/Fe2+∘=0.772V E‌cell ‌∘=E‌cathode ‌∘−E‌anode ‌∘ =0.772−0.539=0.233V Using standard Gibb's free energy, ∆G∘=nFE‌cell ‌∘=+2×96500×0.233 ∆G∘=44969J=44.9kJ=45kJ