What do you mean by exhaustive methylation of amines?

Explanation

### Step-by-Step Solution:

1. **Definition of Exhaustive Methylation**:
Exhaustive methylation of amines refers to the process of converting primary, secondary, and tertiary amines into quaternary ammonium salts through successive methylation reactions.

2. **Starting with Primary Amines**:
Consider a primary amine, such as methylamine (CH₃NH₂). When this primary amine is treated with methyl iodide (CH₃I), a methyl group is transferred to the nitrogen atom.

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