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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 17 March 2021, Shift 1, Chemistry Q43

Question 43 of 90 in this shift, Chemistry question 13 of 30, Section A.

[reaction drawn: see figure_note] Product “A” in the above chemical reaction is :

The figure, in words

Reactant: cyclohexane ring with one ring carbon bearing a CH3 and a two-carbon chain drawn as a single-bond line followed by a double-bond line (top right); arrow with HBr above and CCl4 below; product labelled A (Major Product).
  1. (1)[figure: cyclohexane ring; one ring carbon bears a CH3 and a chain of two carbons ending in Br]
  2. (2)[figure: cyclohexane ring; one ring carbon bears Br and a CH3, the adjacent ring carbon bears a CH3]
  3. (3)[figure: cyclohexane ring; one ring carbon bears Br and a carbon bearing two CH3 groups]Official answer
  4. (4)[figure: cyclohexane ring; one ring carbon bears a CHBr group carrying a CH3, the adjacent ring carbon bears a CH3]

Official answer

Option 3

NTA final key.

Chapter
Hydrocarbons
Topic
Alkenes and Alkynes
Idea tested
Carbocation Rearrangements

Same idea in other shifts

Asked 5× in all
  1. 6 Apr 2023, Shift 2 · Q75In the following reaction, 'B' isHardDiagram basedHas a figure
  2. 24 Feb 2021, Shift 1 · Q41What is the major product formed by HI on reaction with [figure] ?MediumDiagram basedHas a figure
  3. 24 Feb 2021, Shift 1 · Q44What is the final product (major) ‘A’ in the given reaction ? [figure] →HCl\xrightarrow{\mathrm{HCl}} ‘A’ (major product)MediumDiagram basedHas a figure
  4. 2 Sep 2020, Shift 1 · Q41The major product in the following reaction is : 1-methyl-1-vinylcyclopentane (H3C\mathrm{H_3C} and CH=CH2\mathrm{CH=CH_2} on the same ring…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.