Correct Answer:
B. Chlorofluorocarbons (CFCs).
Explanation:
The correct answer is Chlorofluorocarbons (CFCs). because these industrial compounds break down under solar radiation to release destructive chlorine radicals.
- Step 1 (Chemical Dissociation): When non-reactive CFC compounds drift into the stratosphere, they are hit by harsh ultraviolet (UV) light, which breaks their molecular bonds and frees atomic chlorine.
- Step 2 (Catalytic Cycle): A single free chlorine atom acts as a relentless catalyst, systematically breaking apart up to 100,000 vital ozone (O₃) molecules before turning inert.
- Incorrect Options:
- Carbon dioxide is incorrect because CO₂ acts as a prominent greenhouse gas that traps heat in the lower troposphere rather than destroying ozone.
- Nitrogen gas is incorrect because N₂ is an inert, non-destructive element that makes up the vast majority (78%) of Earth's natural atmosphere.
- Methane is incorrect because while CH₄ influences global warming as a potent greenhouse gas, it does not serve as the primary chemical driver of the stratospheric ozone hole.