`H_2O_2` acts as an oxidising agent in

Options

A. Neutral medium
B. Acidic medium
C. Alkaline medium
D. Acidic and alkaline medium

Explanation

To determine in which medium hydrogen peroxide (H₂O₂) acts as an oxidizing agent, we need to analyze its behavior in different pH conditions: acidic, neutral, and alkaline.

### Step-by-Step Solution:

1. **Understanding Oxidizing Agents**: An oxidizing agent is a substance that gains electrons in a chemical reaction and is reduced. For a substance to be a good oxidizing agent, it should have a high reduction potential.

2. **Reduction Potentials in Different Mediums**:
- In **acidic medium**, the standard reduction potential for H₂O₂ is +1.77 V.
- In **alkaline medium**, the standard reduction potential for H₂O₂ is +0.87 V.
- In **neutral medium**, the reduction potential is typically lower than in acidic medium but can vary.

3. **Comparing Reduction Potentials**:
- The higher the reduction potential, the stronger the oxidizing agent. Since +1.77 V (acidic) is greater than +0.87 V (alkaline), H₂O₂ is a stronger oxidizing agent in acidic medium compared to alkaline medium.

4. **Conclusion**:
- H₂O₂ acts as an oxidizing agent in both acidic and alkaline mediums, but it is a better oxidizing agent in acidic medium due to its higher reduction potential.

### Final Answer:
H₂O₂ acts as an oxidizing agent in both acidic and alkaline mediums.

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