Photochemical reaction of nitrogen oxides with unsaturated hydrocarbons produces

Options

A. methyl isocyanate
B. phosgene
C. Benzpyrene
D. peroxy-acyl nitrates.

Answer

To solve the question regarding the photochemical reaction of nitrogen oxides with unsaturated hydrocarbons, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The question mentions nitrogen oxides (NOx) and unsaturated hydrocarbons. Unsaturated hydrocarbons include alkenes and alkynes, which have double or triple bonds.

2. **Understand the Reaction Conditions**: The reaction occurs in the presence of light (photochemical reaction). This means that energy from light is used to initiate the reaction.

3. **Write the General Reaction**: The general form of the reaction can be represented as:
\[ \text{Hydrocarbon} + \text{NO}_2 + \text{Light} \rightarrow \text{Products} \]

4. **Identify the Products**: The specific product formed from the reaction of nitrogen oxides with unsaturated hydrocarbons in the presence of light is known to be peroxyacyl nitrates (PAN). This can be represented as:
\[ \text{Hydrocarbon} + \text{NO}_2 + \text{O}_2 + \text{Light} \rightarrow \text{Peroxyacyl Nitrate (PAN)} \]

5. **Evaluate the Options**: The options provided are:
- Option 1: Methyl isocyanate
- Option 2: Phosgene
- Option 3: Benzopyrene
- Option 4: Peroxyacyl nitrates

From our understanding of the reaction, we can eliminate the first three options:
- Methyl isocyanate (CH3NC) is not produced in this reaction.
- Phosgene is a toxic gas but is not a product of this reaction.
- Benzopyrene is a polycyclic aromatic hydrocarbon and also not a product of this reaction.

6. **Select the Correct Answer**: Therefore, the correct answer is:
\[ \text{Option 4: Peroxyacyl nitrates} \]

### Final Answer:
The photochemical reaction of nitrogen oxides with unsaturated hydrocarbons produces **peroxyacyl nitrates**.

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