JEE Main 2026 — Aldehydes and Ketones Question with Solution
JEE Main 2026 (23 January Shift 1)
Question
' ' is the product which is obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. ' ' is the product which is obtained from the but-2-ene by the ozonolysis followed by hydrolysis. From the following, which product is not obtained when one mole of ' ' and one mole of ' ' react with each other in the presence of alkali followed by heating?
Choose an option
Show full solutionCorrect option: D
Correct answer
D3-Methylbut-2-enal
Step-by-step explanation
Product is obtained by the Stephen reduction of propanenitrile ().
(Propanal).
Product is obtained by the reductive ozonolysis of but-2-ene ().
(Ethanal).
When propanal () and ethanal () react in the presence of alkali followed by heating, they undergo cross-aldol condensation.
Possible products are:
1. Self-aldol of propanal: (2-Methylpent-2-enal).
2. Self-aldol of ethanal: (But-2-enal).
3. Cross-aldol (Ethanal as nucleophile): (Pent-2-enal).
4. Cross-aldol (Propanal as nucleophile): (2-Methylbut-2-enal).
Comparing with the options, 3-Methylbut-2-enal is not formed in any of these reactions.
(Propanal).
Product is obtained by the reductive ozonolysis of but-2-ene ().
(Ethanal).
When propanal () and ethanal () react in the presence of alkali followed by heating, they undergo cross-aldol condensation.
Possible products are:
1. Self-aldol of propanal: (2-Methylpent-2-enal).
2. Self-aldol of ethanal: (But-2-enal).
3. Cross-aldol (Ethanal as nucleophile): (Pent-2-enal).
4. Cross-aldol (Propanal as nucleophile): (2-Methylbut-2-enal).
Comparing with the options, 3-Methylbut-2-enal is not formed in any of these reactions.
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