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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 4 April 2024, Shift 2, Chemistry Q77

Question 77 of 90 in this shift, Chemistry question 17 of 30, Section A.

→ΔKOH(alc)\xrightarrow[\Delta]{\mathrm{KOH(alc)}} major product "P" Product P is

The figure, in words

Reactant: PhCH2-CH(Br)-CH(CH3)2 (benzene ring attached to CH2, then a carbon bearing Br, then an isopropyl group), treated with alcoholic KOH, heat.
  1. (1)[figure: Ph-CH=CH-CH(CH3)2, i.e. phenyl attached to a CH=CH unit bearing an isopropyl group]Official answer
  2. (2)[figure: Ph-CH2-CH=C(CH3)2]
  3. (3)[figure: Ph-CH2-CH2-C(CH3)=CH2]
  4. (4)[figure: Ph-C(=CH2)-CH(CH3)2, i.e. phenyl on a terminal alkene carbon bearing an isopropyl group]

Official answer

Option 1

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
SN1 and SN2 Mechanisms
Idea tested
Temperature Effects on Substitution vs Elimination

Same idea in other shifts

Asked 3× in all
  1. 31 Jan 2024, Shift 1 · Q88CH3CH2Br+NaOH\mathrm{CH_3CH_2Br + NaOH} with C2H5OH\mathrm{C_2H_5OH} gives Product A, and with H2O\mathrm{H_2O} gives Product B. The total number of…EasyNumerical valueHas a figure
  2. 3 Sep 2020, Shift 2 · Q45The major product in the following reaction is : [figure] →Heatt-BuOH\xrightarrow[\text{Heat}]{\text{t-BuOH}}MediumDiagram 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.