Freons which cause damage to ozone layer are

Options

A. Chemically unreactive
B. Non-toxic
C. Odourless
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Freons**:
- Freons are a class of compounds that are primarily used as refrigerants and aerosol propellants. They are known for their stability and non-flammable nature.

2. **Chemical Composition**:
- The most common Freons that are known to cause damage to the ozone layer are CFCl3 (Trichlorofluoromethane) and CF2Cl2 (Dichlorodifluoromethane). These compounds are halogenated hydrocarbons.

3. **Properties of Freons**:
- Freons are characterized by being:
- **Stable**: They do not readily react with other substances under normal conditions.
- **Non-flammable**: They do not catch fire easily.
- **Moderately toxic**: They can be harmful in certain concentrations but are generally considered safe for use in controlled environments.
- **Odorless**: They do not have a noticeable smell.

4. **Impact on the Ozone Layer**:
- When released into the atmosphere, Freons can rise to the stratosphere where they are broken down by ultraviolet (UV) radiation. This process releases chlorine atoms, which can then react with ozone (O3) molecules, leading to the depletion of the ozone layer.

5. **Conclusion**:
- Freons such as CFCl3 and CF2Cl2 are significant contributors to ozone layer depletion due to their stability and the release of chlorine upon breakdown in the stratosphere.