Why is it necessary to control the pH during the reaction of aldehydes and ketones with ammonia derivatives?

Explanation

To answer the question of why it is necessary to control the pH during the reaction of aldehydes and ketones with ammonia derivatives, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- Aldehydes and ketones undergo nucleophilic addition reactions with ammonia derivatives (like primary and secondary amines). This reaction is crucial for forming imines or enamines.

2. **Role of pH**:
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