Aldehydes And Ketones Result Question 45
Passage
Two aliphatic aldehydes $P$ and $Q$ react in the presence of aqueous $\mathrm{K}_2 \mathrm{CO}_3$ to give compound $R$, which upon treatment with $HCN$ provides compound $S$. On acidification and heating, $S$ gives the product shown below :
(2010)

45. The compound R is
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Answer:
Correct Answer: 45. ( a )
Solution:
The given product is an ester, obtained by condensation of a hydroxy acid obtained through hydrolysis of a cyanohydrin :
Acid above is obtained by acid hydrolysis of cyanohydrin $S$ as
$S$ is obtained by nucleophile addition of $HCN$ on $R$, hence $R$ is
$R$ is obtained by treatment of $P$ and $Q$ with aqueous $K _{2}CO _3$ through aldol condensation reaction as