Question

equivalent weight of potassium in different medium like acidic ,basic and neutral why?

Answer 1

KMnO4 has a Molar mass of 158.04 g/mol 

There are two possibillities: 

1. KMnO4 as an oxidizer in acidic media: 
MnO4- + 8 H+ + 5e- --> Mn2+ + 4H2O (gained 5 electrons from reductant) 

I.e. Eq. wt. of KMnO4 = 158.04/5 = 31.61 grams/equivalent 


2. KMnO4 as an oxidizer in basic media: 
MnO4- + 2H2O + 3e- --> MnO2(s) + 4OH- (gained 3 electrons) 

In which case, Eq. wt. of KMnO4 = 158.04/3 = 52.68 grams/equivalent