Question

Which of the following occurs with KMnO\(_4\) in neutral medium?

• A. Oxidation of oxalate ion
• B. Precipitation of sulfur from hydrogen sulfide
• C. Oxidation of Fe\(^{2+}\) to Fe\(^{3+}\)
• D. Oxidation of iodide to iodate

Hint:

KMnO\(_4\) in neutral medium oxidizes iodide (\(I^-\)) to iodate (\(IO_3^-\)).

Answer 1

The Correct Option is D

Step 1: Understanding the Oxidizing Nature of KMnO\(_4\) 
- In an acidic medium, KMnO\(_4\) is a strong oxidizing agent.
- In a neutral medium, its oxidizing power decreases but still oxidizes some species.
Step 2: Oxidation Reactions in Neutral Medium 
- KMnO\(_4\) oxidizes I\(^-\) to IO\(_3^-\) in neutral medium:
\[ 2MnO_4^- + I^- + H_2O \rightarrow IO_3^- + MnO_2 + OH^- \] - Other reactions:
- Oxidation of oxalate ion occurs in acidic medium.
- Precipitation of sulfur from \( H_2S \) occurs in acidic medium.
- Fe\(^{2+}\) to Fe\(^{3+}\) oxidation occurs in acidic medium. 
Thus, the correct answer is Oxidation of iodide to iodate.