Which one of the following is responsible for depletion of the ozone layer in the upper strata of the atmosphere?

Options

A. Polyhalogens
B. Ferrocene
C. Fullerenes
D. Freons

Answer

To answer the question "Which one of the following is responsible for depletion of the ozone layer in the upper strata of the atmosphere?", we need to follow a systematic approach:

### Step-by-Step Solution:

1. **Understanding the Ozone Layer**:
- The ozone layer is located in the stratosphere, which is the second layer of the Earth's atmosphere, above the troposphere. It plays a crucial role in absorbing the majority of the sun's harmful ultraviolet (UV) radiation.

2. **Identifying the Culprits**:
- The primary substances responsible for the depletion of the ozone layer are chlorofluorocarbons (CFCs). These are man-made compounds that were commonly used in refrigeration, air conditioning, and aerosol propellants.

3. **Mechanism of Ozone Depletion**:
- When CFCs are released into the atmosphere, they eventually rise up to the stratosphere. Here, they are broken down by UV radiation, releasing chlorine atoms.
- The chlorine atoms are highly reactive and can react with ozone (O3) molecules. The reaction leads to the formation of chlorine monoxide (ClO) and oxygen (O2).
- The chlorine monoxide can further react with free oxygen atoms, releasing more chlorine atoms and perpetuating the cycle of ozone depletion.

4. **Conclusion**:
- Based on the information, the correct answer to the question is that chlorofluorocarbons (CFCs) are responsible for the depletion of the ozone layer in the upper strata of the atmosphere.

### Final Answer:
Chlorofluorocarbons (CFCs) are responsible for the depletion of the ozone layer in the upper strata of the atmosphere.

---