Q. Which reaction, intermediate is formed during the condensation reaction between acetaldehyde and formaldehyde?
A) $:\overline{C}H_{2}CHO$
B) +
$CH_{2}CHO$
C) +
$CH_{2}OH$
D) $:\overline{C}HCHO$
Explanation
(a)
The $\alpha -$hydrogen atoms of acetaldehyde due to –E effect of [image:12_image676.emf]
group is slightly acidic in nature. In crossed aldol condensation between formaldehyde and acetaldehyde in the first step $OH^{-}$ion (from the base added) abstracts one of these acidic $\alpha -$hydrogens to form carbanion or enolate ion which is stabilised by resonance.
[image:12_image677.emf]
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.