JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Haloalkanes and Haloarenes

Identify the correct set of reagents or reaction conditions 'X' and 'Y' in the following set of transformation.

(A)X = conc.alc. NaOH, 80°C, Y = Br₂/CHCl₃
(B)X = dil.aq. NaOH, 20°C, Y = HBr/acetic acid
(C)X = conc.alc. NaOH, 80°C, Y = HBr/acetic acid✓ Correct
(D)X = dil.aq. NaOH, 20°C, Y = Br₂/CHCl₃

Answer: (C)

Solution

Step X: **conc. alcoholic NaOH at

8 0^{\circ}

C** drives dehydrohalogenation (E2 elimination) of the alkyl halide to the alkene.
Step Y: HBr in acetic acid adds across the double bond by Markovnikov electrophilic addition, giving the secondary bromide.

So X = conc. alc. NaOH,

8 0^{\circ}

C and Y = HBr/acetic acid

\Rightarrow

option C.

JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Single correct option

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