The following reactions show the `H_(2)O_(2)` behaviour in A and B reactions as
(1) `PbS_((s))+4H_(2)O_(2(aq))rarrPbSO_(4(s))+4H_(2)O_((l))`
(2) `HOCl+H_(2)O_(2)rarr H_(3)O^(+)+Cl^(-)+O_(2)`

Options

A. oxidising in acidic medium and reducing in basic medium
B. reducing in acidic medium and oxidising in basic medium
C. oxidising in acidic medium and reducing in acidic medium
D. reducing in acidic medium and oxidising in acidic medium

Answer

To solve the question regarding the behavior of hydrogen peroxide (H₂O₂) in the given reactions A and B, we will analyze each reaction step by step.

### Step 1: Analyze Reaction A
The first reaction is:
\[ \text{PbS}_{(s)} + 4 \text{H}_2\text{O}_2_{(aq)} \rightarrow \text{PbSO}_4_{(s)} + 4 \text{H}_2\text{O}_{(l)} \]

1. **Identify oxidation states**:
- In PbS, lead (Pb) is in the +2 oxidation state and sulfur (S) is in the -2 oxidation state.
- In PbSO₄, lead (Pb) remains +2, sulfur (S) is in the +6 oxidation state (as in sulfate, SO₄²⁻).
- In H₂O₂, the oxidation state of oxygen is -1.

2. **Determine changes in oxidation states**:
- Sulfur changes from -2 in PbS to +6 in PbSO₄, indicating oxidation (loss of electrons).
- Oxygen in H₂O₂ changes from -1 to -2 in water (H₂O), indicating reduction (gain of electrons).

### Conclusion for Reaction A:
- H₂O₂ acts as an **oxidizing agent** because it causes the oxidation of sulfur while being reduced itself.

### Step 2: Analyze Reaction B
The second reaction is:
\[ \text{HOCl} + \text{H}_2\text{O}_2 \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^- + \text{O}_2 \]

1. **Identify oxidation states**:
- In HOCl, chlorine (Cl) is in the +1 oxidation state.
- In O₂, oxygen is in the 0 oxidation state.
- In H₂O₂, oxygen is in the -1 oxidation state.

2. **Determine changes in oxidation states**:
- Oxygen in H₂O₂ goes from -1 to 0 in O₂, indicating oxidation.
- Chlorine in HOCl goes from +1 to -1 in Cl⁻, indicating reduction.

### Conclusion for Reaction B:
- H₂O₂ acts as a **reducing agent** because it is oxidized itself while reducing chlorine.

### Final Summary:
- In reaction A, H₂O₂ is an **oxidizing agent** in an acidic medium.
- In reaction B, H₂O₂ is a **reducing agent** in an acidic medium.

### Final Answer:
C. H₂O₂ behaves as both an oxidizing agent and a reducing agent in acidic medium.

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