Potassium permanganate gives the following reactions in neutral medium `MnO_4^(-) + 2H_2O + 3e^(-) to MnO_2 + 4OH^-` . The equivalent weight of `KMnO_4` is (atomic mass of Mn= 55u )

Options

A. 158
B. 79
C. 52.66
D. 31.6

Answer

C

Explanation

Equivalent weight of `KMnO_2` in neutral medium
`MnO_4^(-) + 2H_2O+ 3e^(-) to MnO_2 + 4OH^-`
Total oxidation state of Mn In `KMnO_4 = 14` units
Total oxidation state of Mn in product `MnO_2 = + 8` units
Change in oxidation state of Mn = 14 - 8 =6 units
` therefore ` Equivalent weight of `KMnO_4`
` = (2M)/(6) =M/3 = 158/3 = 52.66`