Which of the following statements (s) is/are true?
I. Primary and secondary amines react with acid chlorides, anhydrides and esters by nucleophilic substitution reaction this reaction is known as acylation.
II. In the acylation reaction of amines there is replacement of hydrogen atom of `NH_2` or NH group by the acyl group.
Select the correct option.

Options

A. Only I
B. Only II
C. I and II
D. None of these

Answer

To determine the truth of the statements regarding the acylation of amines, let's analyze each statement step by step.

### Step 1: Understand the Reaction of Amines with Acid Chlorides, Anhydrides, and Esters
Primary and secondary amines react with acid chlorides, anhydrides, and esters through a nucleophilic substitution reaction. This reaction is known as acylation.

**Hint:** Look for the type of reaction that occurs when amines interact with carbonyl compounds.

### Step 2: Identify the Mechanism of Acylation
In the acylation reaction, the nitrogen atom of the amine acts as a nucleophile and attacks the electrophilic carbon of the acyl compound (acid chloride, anhydride, or ester). This results in the formation of a tetrahedral intermediate, which eventually leads to the substitution of a hydrogen atom from the amine group (NH2 or NH) by the acyl group (RCO).

**Hint:** Consider what happens to the hydrogen atoms in the amine during the reaction.

### Step 3: Analyze the First Statement
The first statement claims that primary and secondary amines react with acid chlorides, anhydrides, and esters by nucleophilic substitution, and this reaction is called acylation. This statement is true as it accurately describes the reaction process.

**Hint:** Confirm whether the terminology used in the statement matches the standard definitions in organic chemistry.

### Step 4: Analyze the Second Statement
The second statement indicates that in the acylation reaction of amines, there is a replacement of a hydrogen atom of the NH2 or NH group by the acyl group. This is also true, as during the reaction, one of the hydrogen atoms is indeed replaced by the acyl group.

**Hint:** Think about what happens to the functional groups in the amine during the reaction.

### Conclusion
Both statements are true. Therefore, the correct option is that both statements I and II are true.

**Final Answer:** Both statements are true.