Define Photolytic decomposition reaction.

Explanation

### Step-by-Step Text Solution

1. **Understanding the Terms**:
- The term "photolytic" can be broken down into two parts: "photo" which means light, and "lytic" which means to break or decompose.

2. **Definition**:
- A photolytic decomposition reaction is defined as a chemical reaction in which a single substance breaks down into two or more products in the presence of light.

3. **Explanation**:
- In this type of reaction, light energy is absorbed by the substance, which provides the necessary energy to break the chemical bonds within the substance, leading to its decomposition.

4. **Example**:
- A classic example of a photolytic decomposition reaction is the decomposition of silver chloride (AgCl) when exposed to sunlight.
- The reaction can be represented as:
\[ \text{2 AgCl (s)} \xrightarrow{\text{light}} \text{2 Ag (s)} + \text{Cl}_2 (g) \]
- In this reaction, solid silver chloride decomposes into solid silver and chlorine gas upon exposure to light.

5. **Conclusion**:
- Thus, a photolytic decomposition reaction involves the breakdown of a substance into multiple products due to the influence of light.