∴4OH−→2H2O+O2+4e− for 2 mole of H2O=4 F charge is required for 1 mole of H2O=24F=2 F required MnO4−+7→Mn+22+ for 1 mole MnO4−5 F charge is required Ca2++2e−Ca For 1 mole Ca2+ ion required =2 F 1.5 mole Ca2+ ion required =12×1.5=3 F FeO+2→Fe+3O2O3 for 1 mole FeO,1 F charge is required.