Which of the following reaction is employed to produce ozone in the laboratory ?

Options

A. Exposure of air to UV light
B. Reaction of `F_2` with `H_2O`
C. Reaction of `SO_2` with `H_2O_2`
D. Passage of silent electric discharge through oxygen

Answer

To determine which reaction is employed to produce ozone in the laboratory, we need to understand the process involved in ozone formation.

### Step-by-Step Solution:

1. **Understanding Ozone Formation**: Ozone (O₃) is produced from diatomic oxygen (O₂) through a specific process. The key reaction involves the dissociation of O₂ into atomic oxygen (O).

2. **Electric Discharge**: The method used to produce ozone in the laboratory is by passing a silent electric discharge through dry oxygen. This electric discharge provides the energy needed to break the O₂ molecules into individual oxygen atoms.

3. **Dissociation of O₂**: When the electric discharge is applied, the O₂ molecules dissociate into two atomic oxygen (O) atoms:
\[ 2 \text{O}_2 \xrightarrow{\text{Electric Discharge}} 4 \text{O} \]

4. **Formation of Ozone**: The atomic oxygen produced can then react with other O₂ molecules to form ozone (O₃):
\[ \text{O} + \text{O}_2 \rightarrow \text{O}_3 \]

5. **Overall Reaction**: The overall reaction can be summarized as:
\[ 3 \text{O}_2 \xrightarrow{\text{Electric Discharge}} 2 \text{O}_3 \]

6. **Conclusion**: Therefore, the correct method to produce ozone in the laboratory is by passing silent electric discharge through dry oxygen.

### Final Answer:
The reaction employed to produce ozone in the laboratory is:
**Passing silent electric discharge through dry oxygen.**