When hydrogen sulfide reacts with sulfur dioxide to give sulfur and water,

Options

A. Both `H_2S` and `SO_2` are oxidised
B. Both `H_2S` and `SO_2` are reduced
C. `H_2S` is oxidised and `SO_2` is reduced
D. `H_2S` is reduced and `SO_2` is oxidised

Explanation

To solve the question regarding the reaction between hydrogen sulfide (H₂S) and sulfur dioxide (SO₂) to produce sulfur and water, we will follow these steps:

### Step 1: Write the balanced chemical equation for the reaction.
The reaction can be represented as:
\[ 2 \text{H}_2\text{S} + \text{SO}_2 \rightarrow 3 \text{S} + 2 \text{H}_2\text{O} \]

### Step 2: Identify the oxidation states of the elements in the reactants and products.
- In H₂S, the oxidation state of sulfur (S) is -2.
- In SO₂, the oxidation state of sulfur (S) is +4.
- In elemental sulfur (S), the oxidation state is 0.
- In H₂O, the oxidation state of oxygen (O) is -2 and hydrogen (H) is +1.

### Step 3: Determine which species are oxidized and which are reduced.
- **Oxidation** is the loss of electrons or an increase in oxidation state. Here, H₂S is oxidized as sulfur goes from -2 in H₂S to 0 in elemental sulfur.
- **Reduction** is the gain of electrons or a decrease in oxidation state. SO₂ is reduced as sulfur goes from +4 in SO₂ to 0 in elemental sulfur.

### Step 4: Conclude the changes in oxidation states.
- H₂S is oxidized (oxidation state increases from -2 to 0).
- SO₂ is reduced (oxidation state decreases from +4 to 0).

### Step 5: Select the correct answer based on the analysis.
From the analysis, we find that H₂S is oxidized and SO₂ is reduced. Therefore, the correct answer is:
**Option 3: H₂S is oxidized and SO₂ is reduced.**

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