- AThey dissolve in clouds
- UV radiation breaks them apart releasing chlorine atoms
- CThey form acid rain
- DThey become harmless
Correct answer
UV radiation breaks them apart releasing chlorine atoms
Why
In the stratosphere, UV radiation breaks apart CFC and HCFC molecules, releasing chlorine atoms that destroy ozone molecules.
The concept behind this question
Ozone depletion potential (ODP) measures how much damage a compound does to stratospheric ozone, and chlorine is the culprit. CFCs carry the most chlorine and the highest ODP, HCFCs carry less and are transitional, and HFCs contain no chlorine and have an ODP of zero. Zero ODP is not the same as harmless — many HFCs have high global warming potential (GWP), which is what the more recent phase-down addresses.
More questions on this topic
- Which of the following refrigerants has the highest Ozone Depleting Potential (ODP)?
- Where is the ozone layer located?
- What does the ozone layer protect us from?
- Which element in refrigerants is primarily responsible for ozone depletion?
- What type of refrigerant is R-22?
- How many ozone molecules can one chlorine atom destroy?
Exam-style practice question. Not an official EPA exam question.