JEE Main · 2021 · 26 Feb 2021 · Shift 1 · Haloalkanes and Haloarenes

For the given reaction:

What is 'A'?

(A) $CH_{3} CH_{2} CH_{2} NH_{2}$
(B)(see structure)
✓ Correct
(C)(see structure)
(D)(see structure)

Answer: (B)

Solution

Sodamide strips hydrogen bromide from 1-bromoprop-1-ene, and the vinylic halide is dehydrohalogenated to the alkyne:

C H_{3} CH = CHBr NaN H_{2} C H_{3} C \equiv CH

An alkyne passed through a red hot iron tube at

873

K undergoes cyclic polymerisation, three molecules joining into an aromatic ring. Three molecules of propyne combine so that the three methyl groups fall on alternate ring carbons.
A is 1,3,5-trimethylbenzene, mesitylene.

JEE Main · 2021 · 26 Feb 2021 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Haloalkanes and Haloarenes →

More JEE Main questions on Haloalkanes and Haloarenes

The correct order of reactivity of $CH_{3} Br$ in methanol with the following nucleophiles is $F^{-}, I^{-}, C_{2} H_{5} O^{-}$ and $C_{6} H_{5} O^{-}$
JEE Main 2026View solution →
The correct order of the rate of reaction of the following reactants with nucleophile by $S_{N} 1$ mechanism is :
(Given : Structure I and II are rigid)
JEE Main 2026View solution →
The correct order of reactivity of the following benzyl halides towards reaction with KCN is:
JEE Main 2026View solution →
The correct order of the rate of the reaction for the following reaction with respect to nucleophiles is:
$CH_{3} Br + Nu^{Θ} ⟶ CH_{3} Nu + Br^{Θ}$
JEE Main 2026View solution →
Given below are four compounds:
(a) n-propyl chloride
(b) iso-propyl chloride
(c) sec-butyl chloride
(d) neo-pentyl chloride

Percentage of carbon in the one which exhibits optical isomerism is:
JEE Main 2026View solution →
Consider the following reaction :

$(i) NaNH_{2} (ii) ↓ - Br Y$

The product Y formed is :
JEE Main 2026View solution →