Write out the balanced ion electron equation for MnO4- (aq) → Mn2+ (aq)

Balance any oxygen atoms with water molecules MnO4- (aq) → Mn2+ (aq) + 4H2O (l) Balance any H atoms with H+(aq) ions MnO4- (aq) + 8H+ (aq) → Mn2+ (aq) + 4H2O (l) Balance the charges with electrons MnO4- (aq) + 8H+ (aq) + 5e- → Mn2+ (aq) + 4H2O (l)