Learn

Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedHardApplication

JEE Main 4 April 2024, Shift 2, Chemistry Q76

Question 76 of 90 in this shift, Chemistry question 16 of 30, Section A.

Find out the major product formed from the following reaction. [Me : −CH3-\mathrm{CH_3}] →Me2NH (2 equiv)\xrightarrow{\mathrm{Me_2NH\ (2\ equiv)}}

The figure, in words

Reactant: five-membered ring with a C=C at the bottom and a Br on each of the two ring carbons adjacent to the top CH2 (3,5-dibromocyclopentene), reagent Me2NH (2 equiv).
  1. (1)[figure: cyclopentene ring (C=C at the bottom) with an NMe2 group on each of the two ring carbons flanking the top CH2, i.e. the positions that carried Br]
  2. (2)[figure: cyclopentene ring with C=C on the left side and two NMe2 groups on adjacent ring carbons on the right side]Official answer
  3. (3)[figure: cyclopentene ring with C=C on the right side; one NMe2 on the upper-left ring carbon and one NMe2 on the vinylic upper-right carbon]
  4. (4)[figure: cyclopentene ring with C=C at the bottom-left; two NMe2 groups on adjacent carbons at the right, one of them vinylic]

Official answer

Option 2

NTA final key.

Chapter
Amines
Topic
SN1 and SN2 Mechanisms
Idea tested
Allylic and Benzylic Reactivity in SN2

Same idea in other shifts

Asked 3× in all
  1. 9 Apr 2024, Shift 1 · Q73Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : SN2\mathrm{S_N2}…EasyAssertion–reason
  2. 3 Sep 2020, Shift 2 · Q42The decreasing order of reactivity of the following compounds towards nucleophilic substitution (SN2\mathrm{S_N2}) is : (I) [figure] (II)…HardDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.