Question

The equivalent weight of Potassium permanganate in acidic medium is:

• A. 31.6
• B. 51.6
• C. 41.6
• D. 21.6

Answer 1

The Correct Option is A

Step 1: Write the half-reaction in acidic medium.
In acidic solution, permanganate is reduced from Mn7+ to Mn2+:
\[ MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O \]
This shows manganese gains 5 electrons per KMnO4.

Step 2: Find the molecular weight.
Molecular weight of KMnO4 \(= 39 + 55 + 4(16) = 158\).

Step 3: Apply the equivalent weight formula.
\[ \text{Equivalent weight} = \frac{\text{Molecular weight}}{n\text{-factor}} = \frac{158}{5} \]

Step 4: Final Answer.
\[ \boxed{31.6} \]