Learn

Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 24 February 2021, Shift 1, Chemistry Q41

Question 41 of 90 in this shift, Chemistry question 11 of 30, Section A.

What is the major product formed by HI on reaction with [figure] ?

The figure, in words

Stem structure: a carbon bonded to three CH3 groups (upper left, lower left, below) and to a CH group which is double-bonded to CH2 (CH=CH2).
  1. (1)[figure: CH3—C(CH3)(CH3)—CH(H)—CH2I; central carbon drawn with CH3 above, CH3 below, CH3 to the left, bonded to CH (with H drawn below) which is bonded to CH2I]
  2. (2)[figure: CH3—C(CH3 above, I below)—CH(CH3 below)—CH3]Official answer
  3. (3)[figure: CH3—C(CH3 above, CH3 below)—CH(I below)—CH3]
  4. (4)[figure: CH3—CH(CH3 below)—CH(I below)—CH2—CH3]

Official answer

Option 2

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 · Q44What is the final product (major) ‘A’ in the given reaction ? [figure] →HCl\xrightarrow{\mathrm{HCl}} ‘A’ (major product)MediumDiagram basedHas a figure
  3. 17 Mar 2021, Shift 1 · Q43[reaction drawn: see figure_note] Product “A” in the above chemical reaction is :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.