Assertion. Photochemical smog does not involve the condensation of any kind of fog on smoke particles and hence the word smog is a misnomer
Reason. Photochemical smog is due to photochemical oxidation of `SO_2` to `SO_3` which dissolves in moisture of the air to form sulphurous acid which is injurious to health.

Options

A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
C. If Assertion is true but Reason is false
D. If both Assertion and Reason are false

Explanation

To solve the question regarding the assertion and reason about photochemical smog, we will break it down step by step.

### Step 1: Understand the Assertion
The assertion states that "Photochemical smog does not involve the condensation of any kind of fog on smoke particles and hence the word smog is a misnomer."

- **Explanation**: Photochemical smog is primarily a mixture of pollutants, including nitrogen oxides (NOx) and volatile organic compounds (VOCs), which react in the presence of sunlight to form secondary pollutants like ozone. It does not involve the condensation of water vapor on smoke particles, which is characteristic of traditional smog.

### Step 2: Evaluate the Reason
The reason provided states that "Photochemical smog is due to photochemical oxidation of SO₂ to SO₃ which dissolves in moisture of the air to form sulfurous acid which is injurious to health."

- **Explanation**: This statement is incorrect. Photochemical smog is not primarily formed by the oxidation of sulfur dioxide (SO₂) to sulfur trioxide (SO₃). Instead, it is formed by the reaction of nitrogen dioxide (NO₂) with hydrocarbons in the presence of sunlight. The formation of sulfurous acid from SO₂ is related to acid rain, not photochemical smog.

### Step 3: Conclusion
Based on the evaluations:
- The assertion is **true** because photochemical smog does not involve condensation on smoke particles.
- The reason is **false** because it incorrectly describes the formation process of photochemical smog.

### Final Answer
The correct conclusion is that the assertion is true, but the reason is false.