`H_(2)O_(2)` acts as an oxidising agent in

Options

A. Acidic medium only
B. Alkaline medium only
C. Neurtral medium only
D. Acidic and alkaline medium

Answer

To determine in which mediums hydrogen peroxide (H₂O₂) acts as an oxidizing agent, we can analyze its behavior in both acidic and basic conditions through chemical reactions.

### Step-by-step Solution:

1. **Understanding the Role of Hydrogen Peroxide**:
- Hydrogen peroxide can act as both an oxidizing agent and a reducing agent depending on the conditions (acidic or basic).

2. **Reaction in Acidic Medium**:
- Consider the reaction of potassium iodide (KI) with hydrogen peroxide in an acidic medium:
\[ 2 KI + H_2O_2 + 2 H^+ \rightarrow 2 I_2 + 2 H_2O + 2 K^+ \]
- In this reaction, the iodide ion (I⁻) is oxidized to iodine (I₂).
- The oxidation state of iodine changes from -1 in KI to 0 in I₂, indicating that oxidation has occurred.

3. **Conclusion for Acidic Medium**:
- Since hydrogen peroxide facilitates the oxidation of iodide to iodine, it acts as an oxidizing agent in acidic medium.

4. **Reaction in Basic Medium**:
- Now, consider the reaction of manganese(II) sulfate (MnSO₄) with hydrogen peroxide in a basic medium:
\[ 2 MnSO_4 + H_2O_2 + 2 OH^- \rightarrow 2 MnO_2 + H_2O + 2 SO_4^{2-} \]
- In this reaction, the manganese ion (Mn²⁺) is oxidized to manganese dioxide (MnO₂).
- The oxidation state of manganese changes from +2 in MnSO₄ to +4 in MnO₂, indicating that oxidation has occurred.

5. **Conclusion for Basic Medium**:
- Since hydrogen peroxide facilitates the oxidation of manganese in basic medium, it also acts as an oxidizing agent in this environment.

6. **Final Conclusion**:
- Based on the reactions in both acidic and basic mediums, we conclude that hydrogen peroxide acts as an oxidizing agent in both conditions. Therefore, the correct answer is:
- **Hydrogen peroxide acts as an oxidizing agent in acidic and alkaline medium.**