Explain the given reaction with the examples :
Substitution reaction

Explanation

### Step-by-Step Solution:

1. **Definition of Substitution Reaction**:
A substitution reaction is a type of chemical reaction where an atom or a group of atoms in a molecule is replaced by another atom or group of atoms. In organic chemistry, this often involves the replacement of hydrogen atoms in hydrocarbons with other atoms or groups.

2. **Example of Substitution Reaction**:
Consider the reaction between methane (CH₄) and chlorine (Cl₂). When chlorine is introduced to methane in the presence of sunlight, a substitution reaction occurs.

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