In which of the following reaction hydrogen peroxide is a reducing agent

Options

A. `2FeCl_(2)+2HCl+H_(2)O_(2)rarr2FeCl_(3)+2H_(2)O`
B. `Cl_(2)+ H_(2)O_(2)rarr2HCl+O_(2)`
C. `2Hl + H_(2)O_(2)rarr2H_(2)O+l_(2)`
D. `H_(2)SO_(3)+H_(2)O_(2)rarrH_(2)SO_(4)+H_(2)O`

Answer

To determine in which reaction hydrogen peroxide (H₂O₂) acts as a reducing agent, we need to analyze the oxidation states of the elements involved in the reactions provided in the options. Let's go through each option step by step.

### Step-by-Step Solution:

1. **Understand the Role of Hydrogen Peroxide**:
- Hydrogen peroxide can act as both an oxidizing agent and a reducing agent depending on the reaction conditions and the reactants involved.

2. **Analyze Each Option**:
- **Option 1**: \( \text{FeCl}_2 + \text{H}_2\text{O}_2 \rightarrow \text{FeCl}_3 + \text{H}_2\text{O} \)
- In FeCl₂, the oxidation state of Fe is +2, and in FeCl₃, it is +3.
- The oxidation state of Fe increases, indicating that Fe is being oxidized.
- Therefore, H₂O₂ is acting as an oxidizing agent here.
- **Conclusion**: Not correct.

- **Option 2**: \( \text{Cl}_2 + \text{H}_2\text{O}_2 \rightarrow 2 \text{HCl} + \text{O}_2 \)
- The oxidation state of Cl in Cl₂ is 0, and in HCl, it is -1.
- The oxidation state of Cl decreases, indicating that Cl is being reduced.
- Therefore, H₂O₂ is acting as a reducing agent here.
- **Conclusion**: Correct.

- **Option 3**: \( 2 \text{HI} + \text{H}_2\text{O}_2 \rightarrow \text{I}_2 + 2 \text{H}_2\text{O} \)
- The oxidation state of I in HI is -1, and in I₂, it is 0.
- The oxidation state of I increases, indicating that I is being oxidized.
- Therefore, H₂O₂ is acting as an oxidizing agent here.
- **Conclusion**: Not correct.

- **Option 4**: \( \text{HSO}_3^- + \text{H}_2\text{O}_2 \rightarrow \text{HSO}_4^- + \text{H}_2\text{O} \)
- The oxidation state of S in HSO₃⁻ is +4, and in HSO₄⁻, it is +6.
- The oxidation state of S increases, indicating that S is being oxidized.
- Therefore, H₂O₂ is acting as an oxidizing agent here.
- **Conclusion**: Not correct.

3. **Final Answer**:
- The correct option where hydrogen peroxide acts as a reducing agent is **Option 2**: \( \text{Cl}_2 + \text{H}_2\text{O}_2 \rightarrow 2 \text{HCl} + \text{O}_2 \).