Aldehydes and Ketones - Result Question 2
2. In the following reaction,
Carbonyl compound $+MeOH \stackrel{HCl}{\rightleftharpoons \text { acetal }}$
Rate of the reaction is the highest for: $\quad$
(2019 Main, 9 April II)
(a) Acetone as substrate and methanol in excess
(b) Propanal as substrate and methanol in stoichiometric amount
(c) Acetone as substrate and methanol in stoichiometric amount
(d) Propanal as substrate and methanol in excess
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Answer:
Correct Answer: 2. (d)
Solution:
- Key Idea: Aldehydes are more reactive than ketones in nucleophilic addition reactions.
For the reaction,
Carbonyl compound $+MeOH \stackrel{HCl}{\rightleftharpoons}$ Acetal
Rate of reaction is the highest for propanal as substrate and methanol in excess. Propanal is an aldehyde and more reactive than ketones. When $MeOH$ is taken in excess then reaction moves in the forward direction that results in the formation of acetal. Reaction involved is as follows :
BETA
