Q. Which of the following arrangements with respect to their reactivity in nucleophilic addition reaction is correct?
A) acetophenone < benzaldehyde < p-tolualdehyde < p- nitrobenzaldehyde
B) benzaldehyde < acetophenone < p-nitrobenzaldehyde < p-tolualdehyde
C) p- nitrobenzaldehyde < benzaldehyde < p-tolualdehyde < acetophenone
D) acetophenone < p-tolualdehyde < benzaldehyde < p- nitrobenzaldehyde
Explanation
[Solution by Dr. Abubacker] Ketones are less reactive than aldehydes (steric hindrance and +I effect of two groups). Among aromatic aldehydes, the electron-donating $-CH_3$ (p-tolualdehyde) lowers the electrophilicity of the carbonyl carbon, while the electron-withdrawing $-NO_2$ raises it. Order: acetophenone < p-tolualdehyde < benzaldehyde < p-nitrobenzaldehyde. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.