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Friday, 9 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 30 January 2024, Shift 2, Chemistry Q77

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

Products A and B formed in the following set of reactions are B ←B2H6, H2O2, NaOH(aq)\xleftarrow{\mathrm{B_2H_6},\ \mathrm{H_2O_2,\ NaOH(aq)}} [1-methylcyclohexene] →H+/H2O\xrightarrow{\mathrm{H^+/H_2O}} A

The figure, in words

Reaction scheme: 1-methylcyclohexene (double bond at the methyl-bearing carbon) with H+/H2O giving A (right arrow) and with B2H6 then H2O2, NaOH(aq) giving B (left arrow). Options are structures.
  1. (1)A = [figure: 1-methylcyclohexan-1-ol, CH3 and OH on the same ring carbon]; B = [figure: 2-methylcyclohexan-1-ol, CH3 and OH on adjacent ring carbons]Official answer
  2. (2)A = [figure: cyclohexylmethanol, CH2OH on ring]; B = [figure: 2-methylcyclohexan-1-ol, CH3 and OH on adjacent ring carbons]
  3. (3)A = [figure: 2-methylcyclohexan-1-ol, CH3 and OH on adjacent ring carbons]; B = [figure: 1-methylcyclohexan-1-ol, CH3 and OH on the same ring carbon]
  4. (4)A = [figure: cyclohexylmethanol, CH2OH on ring]; B = [figure: 2-(hydroxymethyl)cyclohexan-1-ol, CH2OH and OH on adjacent ring carbons]

Official answer

Option 1

NTA final key.

Chapter
Alcohols, Phenols and Ethers
Topic
Alcohols and Phenols
Idea tested
Hydroboration-Oxidation Regiochemistry

Same topic in other shifts

All Alcohols and Phenols questions
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  3. 5 Apr 2026, Shift 1 · Q67Consider compounds A, B and C with following structural formulae A = CH3−CH2−CH2−CH2−CH2−OH\mathrm{CH_3-CH_2-CH_2-CH_2-CH_2-OH} B =…EasyOtherHas a figure
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  6. 3 Apr 2025, Shift 1 · Q68Number of molecules from below which cannot give iodoform reaction is: Ethanol, Isopropyl alcohol, Bromoacetone, 2−-Butanol,…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 42 of the 174 JEE Main shifts held from 2017 to 2026.