The depletion in the ozone layer is caused by:

Options

A. nitrous oxide
B. carbon dioxide
C. chlorofluorocarbons
D. methane

Answer

**Step-by-Step Solution:**

1. **Understanding the Ozone Layer:**
- The ozone layer is located in the Earth's stratosphere and is crucial for protecting living organisms from harmful ultraviolet (UV) radiation from the sun.

2. **Role of Ozone:**
- Ozone (O3) absorbs most of the sun's harmful UV rays. When UV rays hit ozone, they can break it down into oxygen molecules (O2) and oxygen radicals (O).

3. **Chemical Reactions Involved:**
- The reaction of UV rays with ozone can be represented as:
- O3 + UV → O2 + O (forward reaction)
- This reaction can also occur in reverse, where oxygen can recombine to form ozone.

4. **Impact of Chlorofluorocarbons (CFCs):**
- Chlorofluorocarbons (CFCs) are man-made compounds commonly found in refrigerants, air conditioners, and aerosol sprays.
- When CFCs are released into the atmosphere, they are broken down by UV radiation, releasing chlorine radicals (Cl).

5. **Chlorine Radicals and Ozone Depletion:**
- The chlorine radicals react with ozone in the following way:
- Cl + O3 → ClO + O2
- This reaction is predominantly a forward reaction, meaning it leads to the destruction of ozone without allowing it to reform effectively.

6. **Conclusion:**
- The presence of CFCs in the atmosphere leads to the generation of chlorine radicals, which significantly contributes to the depletion of the ozone layer.
- Therefore, the answer to the question is that the depletion in the ozone layer is primarily caused by chlorofluorocarbons (CFCs).

**Final Answer:**
The depletion in the ozone layer is caused by chlorofluorocarbons (CFCs).

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