JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

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'x' is the product which is obtained by the hydrolysis of prop-1-yne in the presence of mercuric sulphate under dilute acidic medium at 333 K. 'y' is the product which is obtained by the reaction of ethane nitrile with methyl magnesium bromide in dry ether followed by hydrolysis. IUPAC name of product obtained from 'x' and 'y' in the presence of barium hydroxide followed by heating is:

(A)2-Methylpent-4-en-3-one
(B)4-Methylpent-3-en-2-one✓ Correct
(C)4-Methylpent-1-ene
(D)2-Methylpent-3-one

Answer: (B)

Solution

Markovnikov hydration of prop-1-yne with

HgS O_{4} / H_{2} S O_{4}

at 333 K places the oxygen on the internal carbon, giving propan-2-one as

x

. Ethanenitrile adds methylmagnesium bromide to form a ketimine salt that hydrolyses to propan-2-one as

y

. Two molecules of propan-2-one undergo aldol-type condensation with barium hydroxide and then lose water on heating to give

(C H_{3})_{2} C = CH - CO - C H_{3}

, whose IUPAC name is 4-methylpent-3-en-2-one.

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JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

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