An optically active alkyl halide \({\mathrm{C}}_{4}{\mathrm{H}}_{9}\mathrm{Br}[\mathrm{A}]\) reacts with hot \(\mathrm{K…
An optically active alkyl halide \({\mathrm{C}}_{4}{\mathrm{H}}_{9}\mathrm{Br}[\mathrm{A}]\) reacts with hot \(\mathrm{KOH}\) dissolved in ethanol and forms alkene [B] as major product which reacts with bromine to give dibromide [C]. The compound [C] is converted into a gas [D] upon reacting with alcoholic \({\mathrm{NaNH}}_{2}\). During hydration 18 gram of water is added to 1 mole of gas [D] on warming with mercuric sulphate and dilute acid at 333 K to form compound [E]. The IUPAC name of compound [ E ] is
[JEE Main 2025, 2 Apr (Shift 1)]
\(\mathrm{Butan}-2-\mathrm{one}\)
Optically active \({\mathrm{C}}_{4}{\mathrm{H}}_{9}\mathrm{Br}\) must be 2-bromobutane.
2-bromobutane + alcoholic KOH → but-2-ene (major)
but-2-ene + \({\mathrm{Br}}_{2}\) → 2,3-dibromobutane
2,3-dibromobutane + alcoholic \(NaN{H}_{2}\)→ but-2-yne (gas)
Hydration of but-2-yne with \(HgS{O}_{4}\) and dilute acid gives a ketone.
Addition of 18 g water (1 mole) confirms ketone formation.
Final product is butan-2-one.
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