Q68 / 180 · JIPMER 2015 · Chemistry
In order to prepare one litre 1 N solution of $\mathrm{KMnO}_4$, how many grams of $\mathrm{KMnO}_4$ are required, if the solution to be used in acid medium for oxidation?
- A128 g
- B41.75 g
- Correct answerC31.60 g
- D62.34 g
Solution
In acidic medium,
$\begin{aligned} & \mathrm{MnO}_4^{-}+8 \mathrm{H}^{+}+5 e^{-} \longrightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_2 \mathrm{O} \\ & \text { (From } \mathrm{KMnO}_4 \text { ) }\end{aligned}$
Hence, equivalent weight of $\mathrm{KMnO}_4$ in acidic
medium $=\frac{\text { Moleculer weight }}{5}=\frac{158}{5}=31.6$
$\therefore 1 \mathrm{~N}$ solution can be prepared by dissolving 31.6 g $\mathrm{KMnO}_4$ in 1L solution.
Hence, the correct answer is option: 'C'.