JEE Advanced · 2011 · 10 Apr 2011 · Paper 1 · Hydrocarbons

An acyclic hydrocarbon

P

, having molecular formula

C_{6} H_{10}

, gave acetone as the only organic product through the following sequence of reactions, in which

Q

is an intermediate organic compound.

The structure of the compound

Q

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

Answer: (B)

Solution

Compound

P

is 3,3-dimethyl-1-butyne. Upon hydration with

H_{2} SO_{4} / HgSO_{4}

, the terminal alkyne undergoes Markovnikov addition to form a ketone.

The hydration gives:

(CH_{3})_{3} C - CO - CH_{3}

(3,3-dimethyl-2-butanone or pinacolone).

This corresponds to option (B), which shows the structure with the ketone group adjacent to the tert-butyl group.

JEE Advanced · 2011 · 10 Apr 2011 · Paper 1 · Single correct option

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