Question

Assertion (A) : $C{H}_{3}CHO$ is more reactive than $C{H}_{3}COC{H}_3$
Reason (R) : The $>C=O$ group in $C{H}_{3}CHO$ experiences more steric hindrance.

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

Answer 1

The correct option is C Assertion is true but Reason is false

Aldehydes are more reactive than ketones, i.e. $C{H}_{3}CHO$ is more reactive than $C{H}_{3}COC{H}_3$. This is because the carbocation formed in the ketone is stabilized by electron releasing $C{H}_3$ groups from both the sides of carbocation. Whereas, the carbocation formed in aldehyde is stabilized from one side with the electron releasing group $C{H}_3$. At the other side of the carbocation, hydrogen is present which does not impact stabilization of the cation.

But, steric hindrance is not the reason for the difference in reactivities of aldehydes and ketones. So, Assertion is correct while the Reason is incorrect. Hence option C is correct.