Photochemical smog includes the reduction of

Options

A. `SO_(2)`
B. NO
C. `Cl_(2)`
D. `NO_(2)`

Answer

To solve the question regarding photochemical smog and the reduction of specific compounds, we will analyze the components involved in photochemical smog and identify the correct answer.

### Step-by-Step Solution:

1. **Understanding Photochemical Smog**:
- Photochemical smog is a type of air pollution that occurs when sunlight reacts with pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). It is characterized by the presence of various chemical compounds, primarily in urban areas.

2. **Identifying the Components**:
- The question lists four compounds: SO2 (sulfur dioxide), N2 (nitrogen gas), Cl2 (chlorine gas), and NO2 (nitrogen dioxide). We need to determine which of these compounds is reduced in photochemical smog.

3. **Analyzing Each Compound**:
- **SO2**: Sulfur dioxide is a significant pollutant that can contribute to smog, but it does not get reduced in the context of photochemical reactions.
- **N2**: Nitrogen gas is inert and does not participate in photochemical reactions, so it is not relevant here.
- **Cl2**: Chlorine gas is not typically associated with photochemical smog and can have bleaching properties that would negate the smog's characteristics.
- **NO2**: Nitrogen dioxide is a product of the reaction of nitrogen oxides with oxygen in the atmosphere. It can be present in lower concentrations in photochemical smog.

4. **Conclusion**:
- Among the options provided, NO2 is the compound that is present in photochemical smog in reduced quantities. Therefore, the correct answer to the question is **NO2**.

### Final Answer:
Photochemical smog includes the reduction of **NO2**.

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