Read the following statements regarding the PAN (Peroxyacyl nitrates) and select the correct ones.
(i) It is a secondary pollutant present in photochemical smog.
(ii) It is produced by photochemical reactions between hydrocarbons and nitrogen oxides in the presence of sulight or UV radiations.
(iii) It is thermally unstable and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas.
(iv) It is a lacrymatory substance, causing irritation of eyes.

Options

A. (i) and (ii)
B. (iii) and (iv)
C. (i), (ii) and (iii)
D. (i), (ii), (iii) and (iv)

Answer

To determine the correctness of the statements regarding Peroxyacyl Nitrates (PAN), we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement (i): PAN is a secondary pollutant present in photochemical smog.**
- **Analysis:** PAN is indeed classified as a secondary pollutant. It is formed from primary pollutants through photochemical reactions in the atmosphere, particularly in urban areas with high levels of sunlight and pollution. It is also a component of photochemical smog.
- **Conclusion:** This statement is **correct**.

2. **Statement (ii): PAN is produced by photochemical reactions between hydrocarbons and nitrogen oxides in the presence of sunlight or UV radiations.**
- **Analysis:** PAN is formed when hydrocarbons (which are volatile organic compounds) react with nitrogen oxides (NOx) in the presence of sunlight or ultraviolet (UV) radiation. This process is a key part of the formation of secondary pollutants in the atmosphere.
- **Conclusion:** This statement is **correct**.

3. **Statement (iii): PAN is thermally unstable and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas.**
- **Analysis:** PAN is known to be thermally unstable, especially at elevated temperatures. It can decompose into peroxyethanoyl radicals and nitrogen dioxide (NO2) when subjected to heat.
- **Conclusion:** This statement is **correct**.

4. **Statement (iv): PAN is a lacrymatory substance, causing irritation of eyes.**
- **Analysis:** PAN is indeed a lacrymatory agent, meaning it can cause irritation to the eyes and respiratory tract. This is a significant health concern associated with exposure to PAN.
- **Conclusion:** This statement is **correct**.

### Final Conclusion:
All four statements regarding PAN are correct. Therefore, the correct answer is that all statements (1, 2, 3, and 4) are correct.

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