The correct option is B 10 N
Normality is the number of gram or mole equivalents of solute present in one litre of a solution.
Normality (N) =W×1000E×V (in mL)
where,
W = Weight of the solute
E = Equivalent mass of solute
V = Volume of solution in mL
Equivalent mass of solute=Molecular massValence factor
Valence factor is the number of electron released or absorbed.
Reaction of KMnO4 in acidic solution,
MnO−4+8H++5e−→Mn2++4H2O
Here, Mn+7 is reduced to Mn+2. Hence, it gains 5 e− so valence factor is 5
Molecular mass of KMnO4 is 158 g mol−1
E=Molar mass of KMnO4Valence factor=158/5=31.6
Normality (N) =15.8×100031.6× 50
So, Normality of the solution = 10 N