How do MnO2 and KMnO4 behave? Oxidizing or reducing agents?

1 Answer
Dec 14, 2016

Manganese (IV) oxide and KMnO4 are oxidizing agents.

Explanation:

Mn2+ is the reduction product. Because this is a d5 high spin metal centre, its electronic transitions are spin-forbidden, and a solution of Mn2+ is (almost!) completely colourless (very conc. solutions are a pale rose).

So, when we take strongly oxidizing permanganate ion, which is very strongly coloured, the redox reaction has a self-indicating end-point, and decolorizes:

MnO4+8H++5eMn2++4H2O

We habitually use this reaction in redox titrations.