Answer: nitrogen dioxide.
- A carbon dioxide
- B nitrogen dioxide
- C sulfur dioxide
- D methane gas
Correct answer: B. nitrogen dioxide
Explanation: NO₂ photodissociates in sunlight to start the chain of reactions producing ozone and other smog components.
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.