Calculate the equivalent mass of MnO_​2 in the following reaction.
MnO ^₂ -> Mn⁺² + MnO₄​^-
ans. 5M/6
plz explain.

 

Dear student

In the reaction :

MnO₂ -->  Mn²⁺ + MnO₄^-
can be splitted into two reactions.
Equivalent mass of MnO2 is calculated in both cases:

i) MnO₂   -->       Mn²⁺

Here 2 electrons are involved in reduction,so equivalent mass = molar mass /2 = 87/2 = 43.5

ii) MnO₂  -->  MnO₄^-
Here oxidation state changes from (+4 to +7, so three electrons are involved in the reaction.
Equivalent weight = molar mass/3 =87/3 = 29

Regards