Assertion : Both aldehydes and ketones contain carbonyl group.
Reaction : In aldehydes, the functional group is attached to atleast one hydrogen atom.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

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

### Step 1: Understand the Assertion
The assertion states that "Both aldehydes and ketones contain a carbonyl group."

- **Explanation**: The carbonyl group (C=O) is indeed a common functional group in both aldehydes and ketones. In aldehydes, the carbonyl group is located at the end of the carbon chain, while in ketones, it is found within the carbon chain.

### Step 2: Understand the Reason
The reason states that "In aldehydes, the functional group is attached to at least one hydrogen atom."

- **Explanation**: This is true. In aldehydes, the carbonyl carbon is always bonded to at least one hydrogen atom, which distinguishes them from ketones, where the carbonyl carbon is bonded to two other carbon atoms.

### Step 3: Analyze the Relationship
Now we need to determine if the reason correctly explains the assertion.

- **Analysis**: While both statements are true, the reason does not directly explain why both aldehydes and ketones contain a carbonyl group. The presence of the carbonyl group in ketones is not dependent on the presence of hydrogen atoms, as ketones do not have hydrogen attached to the carbonyl carbon.

### Conclusion
- **Final Statement**: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. Therefore, the correct answer is that the assertion is true, the reason is true, but the reason does not explain the assertion.