When moist coloured flowers are added into `SO_(2)` gas the flowers are decolourised because

Options

A. `SO_(2)` absorbs colouring matter
B. `SO_(2)` oxidised vegetable colouring matter
C. `SO_(2)` reduces vegetale colouring matter
D. `SO_(2)` gives colourless product

Answer

To solve the question "When moist coloured flowers are added into SO₂ gas the flowers are decolourised because," we need to analyze the options provided and understand the chemical behavior of sulfur dioxide (SO₂) in the presence of moisture.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- When SO₂ gas comes into contact with water, it forms sulfurous acid (H₂SO₃). However, in the presence of excess water, it can further react to form sulfuric acid (H₂SO₄).
- The reaction can be summarized as:
\[ SO_2 + H_2O \rightarrow H_2SO_3 \quad \text{(or further to H}_2SO_4\text{)} \]

2. **Role of Nascent Hydrogen**:
- During this reaction, nascent hydrogen is produced. Nascent hydrogen is a highly reactive form of hydrogen that can participate in reduction reactions.
- This nascent hydrogen can interact with the colored compounds present in the flowers.

3. **Reduction of Coloring Matter**:
- The colored compounds in the flowers are typically organic pigments that can be reduced to colorless forms.
- The nascent hydrogen reduces these colored compounds, leading to the decolorization of the flowers.

4. **Identifying the Correct Option**:
- Now, we need to analyze the provided options:
- **Option 1**: SO₂ absorbs coloring matter - This is incorrect as SO₂ does not simply absorb the color.
- **Option 2**: SO₂ oxidizes vegetable coloring matter - This is incorrect; SO₂ acts as a reducing agent, not an oxidizing agent.
- **Option 3**: SO₂ reduces vegetable coloring matter - This is correct as SO₂ facilitates the reduction of the coloring matter through nascent hydrogen.
- **Option 4**: SO₂ gives colorless products - This is partially true but does not explain the mechanism of decolorization.

5. **Conclusion**:
- The correct answer is **Option 3**: SO₂ reduces vegetable coloring matter. This reduction leads to the formation of colorless products, which is why the flowers lose their color.

### Final Answer:
**SO₂ reduces vegetable coloring matter.**