in which of the following reactions,` H_2O_2` is acting as a reducing agent?

Options

A. `PbS + 4H_2O_2 rarr PbSO_4 + 4H_2O`
B. `Cl_2 + H_2O, rarr 2HCI + O_2`
C. `2Fe^2 +H_2O_2 rarr 2Fe^(3+) + 2OH`
D. `H_2SO_4 + H_2O_2 rarr H_2SO_4 + H_2O`

Answer

To determine in which of the following reactions \( H_2O_2 \) is acting as a reducing agent, we need to analyze the oxidation states of the elements involved in the reactions. A reducing agent is a substance that donates electrons and is oxidized in the process, while the other substance is reduced.

### Step-by-Step Solution:

1. **Identify the Reactions**: We need to look at the given reactions (not provided here) and identify the oxidation states of the elements involved, particularly focusing on \( H_2O_2 \).

2. **Determine Oxidation States**:
- For \( H_2O_2 \) (hydrogen peroxide), the oxidation state of oxygen is -1.
- In reactions where \( H_2O_2 \) is acting as a reducing agent, it will lose electrons (be oxidized) and increase the oxidation state of oxygen.

3. **Analyze Each Reaction**:
- For each reaction, we need to check if \( H_2O_2 \) is being oxidized (i.e., its oxidation state increases).
- If \( H_2O_2 \) is oxidized, it means it is acting as a reducing agent.

4. **Example Analysis**:
- Consider a reaction where \( Cl_2 \) is reduced to \( HCl \).
- Here, \( Cl_2 \) goes from an oxidation state of 0 to -1 in \( HCl \), indicating that it is gaining electrons (reduction).
- Simultaneously, \( H_2O_2 \) is oxidized, which means it is losing electrons and thus acting as a reducing agent.

5. **Conclusion**:
- After analyzing the reactions, we find that in the reaction where \( Cl_2 \) is reduced to \( HCl \), \( H_2O_2 \) is indeed acting as a reducing agent.

### Final Answer:
In the reaction where \( Cl_2 \) is reduced to \( HCl \), \( H_2O_2 \) is acting as a reducing agent.

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