What is the charge of #Mn# in #KMnO_4#?

1 Answer
Oct 8, 2016

Answer:

Well, the oxidation state of the metal centre is #+VII#.

Explanation:

But the charge on the permanganate ion is #-1#. You have its potassium salt, i.e permanganate is the counterion to #K^+#, and thus it is reasonable that we have a #MnO_4^-# ion. In other words, the charge on the OVERALL ION is #-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)#, a #d^5# 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_2O#

Is this balanced with respect to mass and charge? Don't trust my arithmetic.