One gas bleaches the colour of flowers by reduction and other by oxidation. These gases are

Options

A. `SO_(2)` and `CI_(2)`
B. CO and `CI_(2)`
C. `NH_(3)` and `SO_(2)`
D. `H_(2)` and `Br_(2)`

Answer

To solve the question regarding the gases that bleach the color of flowers by reduction and oxidation, we can follow these steps:

### Step 1: Identify the Gases
The question states that one gas bleaches by reduction and the other by oxidation. We need to identify which gases are known for these properties.

**Hint:** Think about common gases that are used in bleaching processes and their chemical properties.

### Step 2: Recognize the Gases
The two gases that are commonly known for their bleaching properties are:
- **Chlorine (Cl2)**: This gas acts as an oxidizing agent.
- **Sulfur Dioxide (SO2)**: This gas acts as a reducing agent.

**Hint:** Recall the chemical reactions involving these gases and how they interact with colored substances.

### Step 3: Explain the Mechanism
- **Chlorine (Cl2)**: When chlorine gas reacts with water, it produces nascent oxygen (O), which is a powerful oxidizing agent. This nascent oxygen can react with colored compounds, effectively bleaching them by oxidation.

**Reaction:**
\[ Cl_2 + H_2O \rightarrow 2HCl + O \]

- **Sulfur Dioxide (SO2)**: This gas can react with colored substances and release oxygen from them, leading to a loss of color. This process is a reduction reaction.

**Reaction:**
\[ SO_2 + \text{Colored Substance} \rightarrow H_2SO_4 + \text{Colorless Product} \]

**Hint:** Consider how oxidation and reduction processes affect the color of substances.

### Step 4: Conclude the Answer
Based on the identified gases and their mechanisms, we conclude that the two gases that bleach the color of flowers by reduction and oxidation are:
- **Sulfur Dioxide (SO2)** - bleaches by reduction.
- **Chlorine (Cl2)** - bleaches by oxidation.

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

---