KMnO4 in aqueous solution is violet in color and is reduced to Mn2+ which does not color the solution.

MnO4- (aq) + 8 H+(aq) + 5 e- = Mn2+(aq) + 4H2(l)

KMnO4 is often the titrant and reacts with the titrand (analyte). At the equivalence point the solution takes on a violet/purple color.

If KMnO4 is the titrand, then the violet color disappears. However, if the KMnO4 concentration is high enough, MnO2 (brown precipitate) may be formed.

4MnO4- (aq)  + 4H+ (aq)  + 4e- =  4 MnO2 (s)  + 3O2 (aq)  + 2H2O(l)

An example of manganimetric color titration is described in the potassium permanganate index method.

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