Question

Potassium permanganate is titrated against ferrous ammonium sulphate in acidic medium, the equivalent mass of potassium permanganate is:

• A. $\frac{\text{molecular mass}}{3}$
• B. $\frac{\text{molecular mass}}{5}$
• C. $\frac{\text{molecular mass}}{2}$
• D. $\frac{\text{molecular mass}}{10}$

Answer 1

The correct option is B $\frac{\text{molecular mass}}{5}$

The ionic reaction involved in titration is:
$Mn{O}_4^{-}+5F{e}^{2+}+8H^{+}\to M{n}^{2+}+4H_{2}O+5F{e}^{3+}$
Since, a molecule of $KMn{O}_4$ accepts $5$ electrons in acid medium, its equivalent mass will be $\left(\frac{\text{molecular mass}}{5}\right)$.