This section contains Assertion and Reason type questions, Each question has 4 choices (1), (2), (3) and (4), out of which only one is correct.
Assertion (A) Pentan-2-one and pentan-3 one are metamers.
Reason (R) Pentan 2-one and pentan-3-one differ in the position of the keto group.

Options

A. Both Assertion and Reason are true and Reason is the correct explanation of the nAssertion
B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
C. Assertion is correct but Reason is incorrect
D. Reason is correct and Assertion is incorrect

Answer

To solve the assertion and reason question regarding pentan-2-one and pentan-3-one, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that pentan-2-one and pentan-3-one are metamers.
- Metamers are defined as compounds that have the same molecular formula but differ in the arrangement of atoms or groups around a functional group.

2. **Identifying the Compounds**:
- Pentan-2-one has the structure:
```
CH3-CO-CH2-CH2-CH3
```
- Pentan-3-one has the structure:
```
CH3-CH2-CO-CH2-CH3
```
- Both compounds have the same molecular formula (C5H10O), but the position of the keto group (C=O) differs.

3. **Understanding the Reason**:
- The reason states that pentan-2-one and pentan-3-one differ in the position of the keto group.
- In pentan-2-one, the keto group is located at the second carbon, while in pentan-3-one, it is located at the third carbon.

4. **Evaluating the Truth of the Statements**:
- The assertion is true because pentan-2-one and pentan-3-one are indeed metamers.
- The reason is also true as it correctly explains that the difference in the position of the keto group is what distinguishes the two compounds.

5. **Conclusion**:
- Both the assertion and the reason are true. However, the reason provides a correct explanation for the assertion.

### Final Answer:
- The correct choice is that both the assertion and reason are true, and the reason is a correct explanation of the assertion.