But the charge on the permanganate ion is -1−1. You have its potassium salt, i.e permanganate is the counterion to K^+K+, and thus it is reasonable that we have a MnO_4^-MnO−4 ion. In other words, the charge on the OVERALL ION is -1−1; it might lie on the metal or more likely the oxygen, but it is there.
When permanganate is reduced, it goes down to Mn(+II)Mn(+II), a d^5d5 system that is almost colourless. This makes the redox couple very useful for titrations because chemical change can be observed macroscopically in real time by the dramatic colour change.
MnO_4^(-) + 8H^(+) + 5e^(-) rarr Mn^(2+) + 4H_2OMnO−4+8H++5e−→Mn2++4H2O
Is this balanced with respect to mass and charge? Don't trust my arithmetic.
