One gas bleaches the colour of flowers by reduction while the other by oxidation. They are

Options

A. `CO_2 and Cl_2`
B. `H_2 S and Br_2`
C. `Cl_2 and H_2 S`
D. `SO_2 and Cl_2`

Explanation

To solve the question, we need to identify two gases that can bleach the color of flowers through different chemical processes: one by reduction and the other by oxidation.

### Step-by-Step Solution:

1. **Understanding Bleaching Agents**:
- Bleaching agents can remove color from substances, and they can do this through two main chemical processes: oxidation and reduction.

2. **Identifying the Oxidizing Agent**:
- Chlorine gas (Cl₂) is known to act as an oxidizing agent. When chlorine gas reacts with water, it produces hydrochloric acid (HCl) and nascent oxygen (O).
- The nascent oxygen is responsible for the oxidation process, which can bleach colors by oxidizing the colored compounds in flowers.

3. **Identifying the Reducing Agent**:
- Sulfur dioxide (SO₂) is known to act as a reducing agent. When sulfur dioxide reacts with water, it forms sulfuric acid (H₂SO₄) and hydrogen (H).
- The hydrogen produced can reduce colored compounds, leading to a bleaching effect through reduction.

4. **Conclusion**:
- Therefore, the two gases that bleach the color of flowers are:
- Chlorine (Cl₂) - bleaches by oxidation.
- Sulfur dioxide (SO₂) - bleaches by reduction.

### Final Answer:
The gases are Chlorine (Cl₂) and Sulfur Dioxide (SO₂).

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