Q. ${KMnO}_{4}$ (mol.wt.= 158) oxidizes oxalic acid in acid medium to ${CO}_{2}$ and water as follows $5C_{2}O_{4}^{2 -} + 2{MnO}_{4}^{-} + 16H^{+} \rightarrow 10{CO}_{2} + 2{Mn}^{2 +} + 8H_{2}O$ What is the equivalent weight of ${KMnO}_{4}$?

A) 158
B) 31.6
C) 39.5
D) 79
Explanation

(b)
$5C_{2}O_{4}^{2 -} + \begin{matrix}
+ 7 \\
2MnO_{4}^{-}
\end{matrix} + 16H^{+} \rightarrow 10CO_{2} + 2Mn^{2 +} + 8H_{2}O$
Equivalent weight=$\frac{molecular\ weight}{change\ in\ oxidation\ number}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{158}{5} = 31.6$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.