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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 3 August 2021, Shift 1, Chemistry Q42

Question 42 of 90 in this shift, Chemistry question 12 of 30, Section A.

Find out the correct major product from the following reaction (Me = – CH3\mathrm{CH_3})

The figure, in words

Reaction drawn: a cyclohexane ring with C=O (O at top) and, on the adjacent ring carbon, a CH2 chain ending in NMe2; arrow with reagents '1) Me-I' above and '2) NaOH, mild heating' below, then '?'.
  1. (1)[figure: cyclohexane ring with a C=O (O drawn at top) at one ring carbon and an exocyclic C=CH2 double bond at the adjacent ring carbon]Official answer
  2. (2)[figure: cyclohexane ring with C=O at one ring carbon; the adjacent ring carbon carries both a Me group and a CH2–NMe2 group]
  3. (3)[figure: cyclohexane ring with C=O at one ring carbon; one adjacent ring carbon carries Me and the other adjacent ring carbon carries CH2–NMe2]
  4. (4)[figure: cyclohexane ring with C=O at one ring carbon; one ring carbon adjacent to the C=O carbon bears a CH2–NMe2 group, and the other ring carbon adjacent to the C=O carbon is joined by a single bond to a carbon of a second cyclohexane ring that carries an OH; this second ring also bears a CH2–NMe2 group on a ring carbon adjacent to the OH carbon]

Official answer

Option 1

NTA final key.

Chapter
Amines
Topic
Amines
Idea tested
Hofmann Elimination of Quaternary Salts

Same idea in other shifts

Asked 2× in all
  1. 28 Jul 2022, Shift 1 · Q76Identify the correct statement for the below given transformation. CH3−CH2−CH2−CH−CH3\mathrm{CH_3-CH_2-CH_2-CH-CH_3} with N⊕(CH3)3\mathrm{N^{\oplus}(CH_3)_3} on…MediumSingle correct

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.