Question

The equivalent weight of potassium permanganate when it acts as oxidizing agent in ferrous ion estimation is:

• A. 158
• B. 31.6
• C. 79
• D. 39.5

Hint:

The equivalent weight of an oxidizing agent like potassium permanganate is calculated based on the molar mass divided by the change in oxidation state.

Answer 1

The Correct Option is B

Step 1: Equivalent weight calculation. The equivalent weight of potassium permanganate \( KMnO_4 \) in the oxidation of ferrous ions depends on the change in oxidation state of manganese. For potassium permanganate, the change in oxidation state is 5 (from +7 to +2). The equivalent weight is calculated as: \[ \text{Equivalent weight} = \frac{\text{Molar mass}}{\text{Change in oxidation state}} = \frac{158}{5} = 31.6 \]
Step 2: Conclusion. Thus, the correct answer is 31.6.