Write one chemical equation to show that `SO_2` acts as a reducing agent.

Explanation

To demonstrate that sulfur dioxide (SO₂) acts as a reducing agent, we can write a chemical equation where SO₂ reduces another species while being oxidized itself. Here’s a step-by-step solution:

### Step 1: Identify the Reaction
We need to find a suitable reaction where SO₂ can act as a reducing agent. A common reaction is the reduction of iron(III) ions (Fe³⁺) to iron(II) ions (Fe²⁺) in an acidic medium.

### Step 2: Write the Half-Reactions
1. **Oxidation half-reaction (for SO₂):**
\[
...