Which of the following statement is incorrect about the reaction of ammonia derivatives with carbonyl compounds?

Options

A. pH of solution is maintained between 3 to 4
B. Addition of ammonia derivatives occurs followed by elimination of `H_(2)O`
C. At very low pH (less than 3) ammonia derivatives are protonated and do not act as nucleophile
D. At very high pH reaction becomes explosive

Answer

To determine which statement is incorrect about the reaction of ammonia derivatives with carbonyl compounds, we will analyze each statement based on our understanding of the chemistry involved.

### Step-by-Step Solution:

1. **Understanding the Reaction Context**:
- Ammonia derivatives (like primary amines) react with carbonyl compounds (aldehydes and ketones) to form imines or enamines. This reaction typically involves nucleophilic addition followed by dehydration (loss of water).

2. **Analyzing Each Statement**:
- **Statement 1**: "The pH of the solution is maintained between 3 to 4."
- This statement is true. The optimum pH for the reaction to proceed effectively is around 3.5, which falls within the range of 3 to 4.

- **Statement 2**: "The addition of ammonia derivative occurs followed by the elimination of water."
- This statement is also true. The reaction mechanism involves the nucleophilic attack of the ammonia derivative on the carbonyl carbon, followed by the elimination of a water molecule to form an imine.

- **Statement 3**: "At very low pH i.e. less than 3, ammonia derivatives are protonated and do not act as a nucleophile."
- This statement is true. At very low pH, the ammonia derivative can become protonated, forming an ammonium ion, which cannot act as a nucleophile due to the lack of a lone pair.

- **Statement 4**: "At very high pH the reaction becomes explosive."
- This statement is incorrect. At high pH, the carbonyl group becomes less reactive towards nucleophiles, and the reaction does not proceed explosively. Instead, the reaction rate decreases.

3. **Conclusion**:
- The incorrect statement among the options provided is **Statement 4**.

### Final Answer:
The incorrect statement about the reaction of ammonia derivatives with carbonyl compounds is **Statement 4**: "At very high pH the reaction becomes explosive."

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