`SO_(2)` bleaches by

Options

A. Reduction
B. Oxidation
C. Hydrolysis
D. None of above

Answer

To solve the question "SO₂ bleaches by", we need to analyze the properties and reactions of sulfur dioxide (SO₂) in the context of its bleaching action.

### Step-by-Step Solution:

1. **Understanding Bleaching Agents**: Bleaching agents are substances that can remove color from materials. Common bleaching agents include chlorine and sulfur dioxide.

**Hint**: Remember that bleaching agents can work through different mechanisms, such as oxidation or reduction.

2. **Identifying the Mechanism of SO₂**: Sulfur dioxide (SO₂) is known to act as a reducing agent. This means it can donate electrons to other substances, which can lead to the removal of oxygen from colored compounds.

**Hint**: Recall the definitions of oxidation and reduction. Oxidation involves the loss of electrons (or gain of oxygen), while reduction involves the gain of electrons (or loss of oxygen).

3. **Comparison with Chlorine**: While chlorine is a bleaching agent that works through oxidation (gaining electrons), sulfur dioxide bleaches by reduction (losing oxygen).

**Hint**: Think about how different substances interact with colored compounds. Chlorine adds oxygen, while sulfur dioxide removes it.

4. **Effect of Atmospheric Oxygen**: It is important to note that the bleaching effect of SO₂ can be temporary. Atmospheric oxygen can eventually replace the oxygen that was removed, causing the material to regain its color.

**Hint**: Consider the stability of the bleaching effect and how external factors can influence it.

5. **Conclusion**: Based on the above analysis, we conclude that sulfur dioxide (SO₂) bleaches by reduction.

**Hint**: Look for keywords in the question that indicate the type of reaction (e.g., "bleaches by" suggests a specific mechanism).

### Final Answer:
SO₂ bleaches by **reduction**.