Assertion: Tertiary amines undergo acylation reaction.
Reason : Tertiary amines do not have replaceable H atom.

Answer

To solve the given question, we need to analyze the assertion and reason provided.

### Step 1: Understanding the Assertion
**Assertion:** Tertiary amines undergo acylation reaction.

- Tertiary amines have the general structure R3N, where R can be any alkyl or aryl group.
- Acylation involves the introduction of an acyl group (RCO-) into a compound. In the case of amines, this typically requires the presence of a hydrogen atom attached to the nitrogen atom to form a stable product.

### Step 2: Understanding the Reason
**Reason:** Tertiary amines do not have replaceable H atom.

- Tertiary amines do not have any hydrogen atoms attached to the nitrogen atom (N). Instead, they have three alkyl or aryl groups attached. This means that there are no hydrogen atoms that can be replaced during the acylation reaction.

### Step 3: Conclusion
- Since tertiary amines lack a replaceable hydrogen atom, they cannot undergo acylation reactions. Therefore, the assertion that "tertiary amines undergo acylation reaction" is false.
- The reason provided is true, as it correctly states that tertiary amines do not have a replaceable hydrogen atom.

### Final Answer:
- The assertion is false, and the reason is true. Therefore, the correct response to the question is that the assertion does not support the reason.

---