Answer: a chlorofluorocarbon.
- A plain carbon dioxide
- B a chlorofluorocarbon
- C ordinary water vapour
- D molecular oxygen
Correct answer: B. a chlorofluorocarbon
Explanation: CFCs are both potent greenhouse gases and ozone-depleting; each molecule traps far more heat than CO₂.
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.