Answer: nitrogen.
- A carbon
- B nitrogen
- C hydrogen
- D helium
Correct answer: B. nitrogen
Explanation: SO₂ and NOₓ dissolve in rain to form sulfuric and nitric acids, lowering its pH.
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.