Dry `SO_(2)` does not bleach dry flowers because

Options

A. nascent hydrogen responsible for bleaching is produced only in presence of moisture
B. water is the actual reducing agent responsible for bleaching
C. water is stronger acid than `SO_(2)`
D. the `OH^(-)` ions produced by water cause bleaching.

Answer

To solve the question "Dry SO₂ does not bleach dry flowers because...", we need to understand the role of moisture in the bleaching process involving sulfur dioxide (SO₂). Here's a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Identify the Bleaching Agent**:
- The bleaching agent in this context is sulfur dioxide (SO₂).

2. **Understand the Condition**:
- The question specifies "dry SO₂" and "dry flowers". This indicates that there is no moisture present in either the SO₂ or the flowers.

3. **Role of Moisture in Bleaching**:
- For SO₂ to exhibit its bleaching properties, it needs to react with water (moisture). In the presence of moisture, SO₂ can produce nascent hydrogen, which is a reactive form of hydrogen that can bleach colored substances.

4. **Chemical Reaction**:
- When SO₂ reacts with water (H₂O), it forms sulfuric acid (H₂SO₄) and nascent hydrogen:
\[ SO₂ + H₂O \rightarrow H₂SO₄ + \text{nascent hydrogen} \]

5. **Bleaching Mechanism**:
- The nascent hydrogen produced in the reaction is responsible for the bleaching effect. It reacts with colored compounds in the flowers, leading to decolorization.

6. **Conclusion**:
- Since there is no moisture present in the case of dry SO₂ and dry flowers, nascent hydrogen cannot be produced. Therefore, dry SO₂ cannot bleach dry flowers.

7. **Final Answer**:
- The correct reason why dry SO₂ does not bleach dry flowers is that nascent hydrogen, which is responsible for bleaching, is produced only in the presence of moisture.