Cosider the reactions
(i) `H_(2)O_(2) + 2HI to I_(2) + 2H_(2)O`
(ii) `HOCl + H_(2)O_(2) to H_(3)O^(+) + Cl^(-) + O_(2)`
Which of the following statements is correct about `H_(2)O_(2)` with reference to these reactions ? Hydrogen peroxide is ………

Options

A. an oxidising agent in both (i) and (ii)
B. an oxidising agent in (ii) and reducing agent in(ii)
C. a reducing agent in (i) and oxidising agent in (ii)
D. a reducing agent in both (i) and (ii)

Explanation

To determine the role of hydrogen peroxide (H₂O₂) in the given reactions, we will analyze each reaction step by step, focusing on the oxidation states of the elements involved.

### Step 1: Analyze the first reaction
**Reaction (i):**
\[ \text{H}_2\text{O}_2 + 2\text{HI} \rightarrow \text{I}_2 + 2\text{H}_2\text{O} \]

1. **Identify oxidation states:**
- In H₂O₂, the oxidation state of oxygen is -1.
- In HI, iodine (I) has an oxidation state of -1.
- In I₂, iodine has an oxidation state of 0.
- In H₂O, oxygen has an oxidation state of -2.

2. **Determine changes in oxidation states:**
- Oxygen in H₂O₂ changes from -1 to -2 (reduction).
- Iodine in HI changes from -1 to 0 (oxidation).

3. **Conclusion:**
- Since H₂O₂ causes the oxidation of HI (iodine), it acts as an **oxidizing agent** in this reaction.

### Step 2: Analyze the second reaction
**Reaction (ii):**
\[ \text{HOCl} + \text{H}_2\text{O}_2 \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^- + \text{O}_2 \]

1. **Identify oxidation states:**
- In HOCl, chlorine (Cl) has an oxidation state of +1.
- In H₂O₂, the oxidation state of oxygen is -1.
- In H₃O⁺, oxygen has an oxidation state of -2.
- In Cl⁻, chlorine has an oxidation state of -1.
- In O₂, oxygen has an oxidation state of 0.

2. **Determine changes in oxidation states:**
- Chlorine in HOCl changes from +1 to -1 (reduction).
- Oxygen in H₂O₂ changes from -1 to 0 (oxidation).

3. **Conclusion:**
- Since H₂O₂ causes the reduction of chlorine (from +1 to -1), it acts as a **reducing agent** in this reaction.

### Final Conclusion
- In the first reaction, H₂O₂ acts as an oxidizing agent.
- In the second reaction, H₂O₂ acts as a reducing agent.

Thus, the correct statement about H₂O₂ is that it is an **oxidizing agent in the first reaction and a reducing agent in the second reaction**.

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