Arrange the following in decreasing order of their reactivity towards nucleophilic addition reaction
A. \(CH_3CHO\)
B. \(CH_3CH_2CHO\)
C. \(CH_3COCH_3\)
D. \(CH_3COCH_2CH_3\)
E. \(C_6H_5COCH_3\)
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A, B, C, D, E
Reactivity towards nucleophilic addition depends on how easily a nucleophile can reach the carbonyl carbon and how positive that carbon is:
Within each class, a larger alkyl group adds more crowding and more +I effect: \( \ce{CH3CHO} \) > \( \ce{CH3CH2CHO} \) and \( \ce{CH3COCH3} \) > \( \ce{CH3COCH2CH3} \).
Acetophenone (E) is the least reactive: the benzene ring is bulky and its resonance with the C=O group lowers the positive charge on the carbonyl carbon.
NCERT (2026-27 edition):
Reactivity
