Answer: below 5.6.
- A above 7
- B below 5.6
- C equal to 7
- D exactly 14
Correct answer: B. below 5.6
Explanation: Acid rain has a pH below the natural 5.6 owing to dissolved SO₂ and NOₓ.
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.