Question

Which of the following is responsible for the depletion of the ozone layer?

• A. Sulphur
• B. Carbon dioxide
• C. Carbon
• D. Chlorofluorocarbon

Hint:

The Montreal Protocol (1987) was an international treaty to phase out CFCs and protect the ozone layer.

Answer 1

The Correct Option is D

Step 1: Conceptual Background:
The ozone layer in the stratosphere protects life on Earth by absorbing harmful ultraviolet (UV) radiation. However, human activities have caused its depletion. The major chemicals responsible are chlorofluorocarbons (CFCs), which were widely used in refrigerators, air conditioners, and aerosol sprays. Step 2: Analysis of Options:
Sulphur: Leads to acid rain but does not affect ozone layer directly.
Carbon dioxide (CO$_2$): Causes global warming, not ozone depletion.
Carbon: Element itself has no role in ozone destruction.
Chlorofluorocarbons (CFCs): Release chlorine atoms in the stratosphere, which break ozone (O$_3$) molecules into oxygen (O$_2$), reducing the protective layer.
Step 3: Detailed Explanation:
Each chlorine atom from CFCs can destroy thousands of ozone molecules. This results in the thinning of the ozone layer, commonly referred to as the “ozone hole”, especially observed over Antarctica.
Step 4: Final Answer:
The chemical mainly responsible for ozone depletion is Chlorofluorocarbon (CFC).