Answer: Both assertion and reason are true and the reason explains the assertion.
- A The assertion is false but the reason is true
- B Both statements are true but the reason does not correctly explain the assertion
- C The assertion is true but the reason is false
- D Both assertion and reason are true and the reason explains the assertion
Correct answer: D. Both assertion and reason are true and the reason explains the assertion
Explanation: CO<sub>2</sub> traps outgoing IR (greenhouse effect) but, unlike CFCs, it produces no chlorine or other radicals that catalyse ozone breakdown, so the reason correctly explains the assertion.
Classical smog is a reducing mixture of SO₂ and fog, while photochemical smog is an oxidising mixture generated by UV-driven reactions of NOx and hydrocarbons.
Concept context
Understand how human activities alter the atmosphere, water, and soil. Covers air pollutants, smog types, ozone depletion, acid rain, greenhouse effect, water and soil pollution, and the principles of green chemistry.