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

Options

A. `2FeCl_(2) + 2CHl +H_(2)O_(2) rarr 2FeCl_(3)+2H_(2)O`
B. `Cl_(2)+H_(2)O_(2)rarr 2HCl+O_(2)`
C. `2HI+H_(2)O_(2)rarr 2H_(2)O+I_(2)`
D. `H_(2)SO_(3)+H_(2)O_(2)rarrH_(2)SO_(4)+H_(2)O`

Explanation

To determine in which reaction hydrogen peroxide (H2O2) acts as a reducing agent, we will analyze each of the provided reactions step by step.

### Step-by-Step Solution:

1. **Identify the Reactions**: We have four reactions to analyze:
- Reaction 1: \( 2FeCl_3 + 2SCl + H_2O_2 \rightarrow 2FeCl_2 + 2S_2 \)
- Reaction 2: \( Cl_2 + H_2O_2 \rightarrow 2SCl + O_2 \)
- Reaction 3: \( 2HI + H_2O_2 \rightarrow 2H_2O + I_2 \)
- Reaction 4: \( H_2SO_3 + H_2O_2 \rightarrow H_2SO_4 + H_2O \)

2. **Analyze Reaction 1**:
- **Oxidation States**:
- In \( FeCl_3 \), the oxidation state of Fe is +3.
- In \( FeCl_2 \), the oxidation state of Fe is +2.
- **Change**: Fe is reduced (gains electrons), so H2O2 acts as an oxidizing agent here.

3. **Analyze Reaction 2**:
- **Oxidation States**:
- In \( Cl_2 \), the oxidation state of Cl is 0.
- In \( SCl \), the oxidation state of Cl is -1.
- **Change**: Cl is reduced (gains electrons), so H2O2 acts as a reducing agent here.

4. **Analyze Reaction 3**:
- **Oxidation States**:
- In HI, the oxidation state of I is -1.
- In I2, the oxidation state of I is 0.
- **Change**: I is oxidized (loses electrons), so H2O2 acts as an oxidizing agent here.

5. **Analyze Reaction 4**:
- **Oxidation States**:
- In \( H_2SO_3 \), the oxidation state of S is +4.
- In \( H_2SO_4 \), the oxidation state of S is +6.
- **Change**: S is oxidized (loses electrons), so H2O2 acts as an oxidizing agent here.

6. **Conclusion**:
- From the analysis, we find that hydrogen peroxide acts as a reducing agent only in **Reaction 2**: \( Cl_2 + H_2O_2 \rightarrow 2SCl + O_2 \).

### Final Answer:
**Hydrogen peroxide is a reducing agent in Reaction 2.**

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