In which of the following reaction `H_(2)O_(2)` acts as reducing agent :-

Options

A. `2FeCl_(2)+2HCl+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)rarr H_(2)SO_(4)+H_(2)O`

Answer

To determine in which reaction \( H_2O_2 \) acts as a reducing agent, we need to analyze the oxidation states of the elements involved in the reactions. Here’s a step-by-step solution:

### Step 1: Understand the Role of \( H_2O_2 \)
Hydrogen peroxide (\( H_2O_2 \)) can act both as an oxidizing agent and a reducing agent depending on the reaction conditions.

### Step 2: Identify the Oxidation States
- In \( H_2O_2 \), the oxidation state of oxygen is -1.
- In water (\( H_2O \)), the oxidation state of oxygen is -2.
- In molecular oxygen (\( O_2 \)), the oxidation state of oxygen is 0.

### Step 3: Determine the Change in Oxidation States
- When \( H_2O_2 \) is converted to \( H_2O \), it is being oxidized (from -1 to -2), which means it acts as an oxidizing agent.
- When \( H_2O_2 \) is converted to \( O_2 \), it is being reduced (from -1 to 0), which means it acts as a reducing agent.

### Step 4: Analyze the Given Options
We need to analyze each option to see if \( H_2O_2 \) is converting to \( O_2 \) (acting as a reducing agent) or \( H_2O \) (acting as an oxidizing agent).

1. **Option A**: \( H_2O_2 \) → \( H_2O \) (Oxidizing agent)
2. **Option B**: \( H_2O_2 \) → \( O_2 \) (Reducing agent)
3. **Option C**: \( H_2O_2 \) → \( H_2O \) (Oxidizing agent)
4. **Option D**: \( H_2O_2 \) → \( H_2O \) (Oxidizing agent)

### Step 5: Conclusion
From the analysis, \( H_2O_2 \) acts as a reducing agent only in **Option B**, where it is converted to \( O_2 \).

### Final Answer
**Option B** is the correct choice where \( H_2O_2 \) acts as a reducing agent.

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