When 1 mole of PbS reacts completely with `H_(2)O_(2)`

Options

A. `H_(2)` is liberated
B. `O_(2)` is liberated
C. 4 moles of `H_(2)O_(2)` consumed
D. Sulphur is converted to sulphite

Answer

To solve the question about the reaction between lead sulfide (PbS) and hydrogen peroxide (H₂O₂), we will follow these steps:

### Step 1: Write the chemical equation for the reaction.
When lead sulfide reacts with hydrogen peroxide, the products formed are lead sulfate (PbSO₄) and water (H₂O). The balanced equation for the reaction is:

\[ \text{PbS} + 4 \text{H}_2\text{O}_2 \rightarrow \text{PbSO}_4 + 4 \text{H}_2\text{O} \]

### Step 2: Identify the oxidation states of sulfur in the reactants and products.
- In PbS, sulfur (S) has an oxidation state of -2.
- In PbSO₄, sulfur (S) has an oxidation state of +6.

### Step 3: Determine the change in oxidation state.
The oxidation state of sulfur changes from -2 in PbS to +6 in PbSO₄, indicating that sulfur is oxidized.

### Step 4: Identify the role of hydrogen peroxide.
Hydrogen peroxide (H₂O₂) acts as an oxidizing agent in this reaction. It gets reduced in the process, as the oxygen in H₂O₂ has an oxidation state of -1 and is converted to -2 in water (H₂O).

### Step 5: Count the moles of H₂O₂ consumed.
From the balanced equation, we see that 4 moles of H₂O₂ are required to react with 1 mole of PbS.

### Step 6: Analyze the options given in the question.
- **Option A**: Hydrogen is liberated - Incorrect.
- **Option B**: Oxygen is liberated - Incorrect.
- **Option C**: 4 moles of H₂O₂ are consumed - Correct.
- **Option D**: Sulfur is converted to sulfite - Incorrect (it is converted to sulfate).

### Conclusion:
The correct answer is that 4 moles of H₂O₂ are consumed in the reaction.

---