Question

Identify the correct statement about the following reaction:
2H₂S + SO₂ → 2H₂O + S

• A. H₂S is oxidising agent and SO₂ is reducing agent.
• B. H₂S is reduced to sulphur.
• C. SO₂ is oxidising agent and H₂S is reducing agent.
• D. SO₂ is oxidised to sulphur.

Answer 1

The Correct Option is C

Step 1: Understanding the reaction:
The given reaction is:
2H₂S + SO₂ → 2H₂O + S.
This is a redox reaction where the oxidation states of elements change. To identify the oxidising and reducing agents, we need to determine how the oxidation states of sulfur change.

Step 2: Oxidation states of sulfur in the reactants and products:
- In H₂S, the oxidation state of sulfur is –2.
- In SO₂, the oxidation state of sulfur is +4.
- In H₂O, the oxidation state of sulfur is –2 (since sulfur is part of H₂O, and the oxidation state of hydrogen is +1).
- In sulfur (S), the oxidation state is 0.

Step 3: Identifying the agents:
- Oxidation: The substance that loses electrons is oxidised. In this reaction, H₂S (sulfur in H₂S changes from –2 to 0) is oxidised.
- Reduction: The substance that gains electrons is reduced. In this reaction, SO₂ (sulfur in SO₂ changes from +4 to 0) is reduced.

Therefore, SO₂ is the oxidising agent (since it is reduced) and H₂S is the reducing agent (since it is oxidised).

Conclusion:
The correct statement is: SO₂ is oxidising agent and H₂S is reducing agent.