Question

$25ml$ of $0.1M$ $KMn{O}_4$ is reduced by $25ml$ of Mohr's salt solution, the molarity of the later is:

• A. $0.5$
• B. $0.2$
• C. $0.1$
• D. $0.05$

Answer 1

The correct option is A $0.5$

Complete reduction of Potassium Permanganate implies the number of equivalents of $KMn{O}_4$ equal the number of equivalents of Mohr's salt.

Valency factor of Mohr's salt is 1. $\therefore Normality=Molarity$

Valency factor of $KMn{O}_4$ is 5. $\therefore Normality=5\times Molarity$

Using stoichiometry,

$E{q}_{moh{r}^{\prime }ssalt}=E{q}_{KMn{O}_4}$

$M\times 25=5\times 0.1\times 25$

$M_{moh{r}^{\prime }ssalt}=0.5M$