Chlorofluorocarbons are damaging to the ozone layer because in the stratosphere they
- A. dissolve ozone directly
- B. release chlorine radicals under ultraviolet light, and each radical destroys many ozone molecules in a chain reaction
- C. react with oxygen to form carbon dioxide
- D. absorb all incoming ultraviolet radiation harmlessly
Explanation
Ultraviolet light breaks the carbon to chlorine bond homolytically, and the chlorine radical produced converts ozone to oxygen and is then regenerated, so a single radical can destroy thousands of ozone molecules before it is removed. Their very stability in the lower atmosphere is what allows them to reach the stratosphere intact. This is why the Montreal Protocol phased them out in favour of hydrofluorocarbons.