JEE Advanced · 2010 · 11 Apr 2010 · Paper 2 · Aldehydes Ketones and Carboxylic Acids

Two aliphatic aldehydes P and Q react in the presence of aqueous

K_{2} CO_{3}

to give compound R, which upon treatment with HCN provides compound S. On acidification and heating, S gives the product shown below :

The compound R is

(A)(see structure)
✓ Correct
(B)(see structure)
(C)(see structure)
(D)(see structure)

Answer: (A)

Solution

From the previous question, P = (CH₃)₂CHCHO and Q = HCHO undergo aldol condensation. The product R is the β-hydroxy aldehyde: (CH₃)₂C(CH₂OH)CHO. This structure has the gem-dimethyl group and a hydroxymethyl group attached to the carbon bearing the aldehyde.

JEE Advanced · 2010 · 11 Apr 2010 · Paper 2 · Single correct option

Practise more: all JEE Advanced PYQs on Aldehydes Ketones and Carboxylic Acids →

More JEE Advanced questions on Aldehydes Ketones and Carboxylic Acids

The sum of total number of carbonyl groups $(> C = O)$ present in the major products X and Y in the following reactions is ____.
JEE Advanced 2026View solution →
The major products obtained from the reactions in List-II are the reactants for the named reactions mentioned in List-I. Match each entry in List-I with the appropriate entry in List-II and choose the correct options.

List-I
(P) Stephen reaction
(Q) Sandmeyer reaction
(R) Hoffma …
JEE Advanced 2025View solution →
The correct reaction/reaction sequence that would produce a dicarboxylic acid as the major product is
JEE Advanced 2025View solution →
Reaction of iso-propylbenzene with $O_{2}$ followed by the treatment with $H_{3} O^{+}$ forms phenol and a by-product P. Reaction of P with 3 equivalents of $Cl_{2}$ gives compound Q. Treatment of Q with $Ca (OH)_{2}$ produces c …
JEE Advanced 2024View solution →
Complete reaction of acetaldehyde with excess formaldehyde, upon heating with conc. NaOH solution, gives P and Q. Compound P does not give Tollens' test, whereas Q on acidification gives positive Tollens' test. Treatment of P with excess cyclohexanone in the presence of catalytic …
JEE Advanced 2024View solution →
The option(s) with correct sequence of reagents for the conversion of $P$ to $Q$ is(are) :
JEE Advanced 2024View solution →