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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 8 April 2024, Shift 1, Chemistry Q78

Question 78 of 90 in this shift, Chemistry question 18 of 30, Section A.

Identify the major products A and B respectively in the following set of reactions. [figure: 1-methylcyclohexan-1-ol (ring carbon bearing CH3 and OH); with conc. H2SO4\mathrm{H_2SO_4}, Δ\Delta giving A; with CH3COCl\mathrm{CH_3COCl}, pyridine giving B]

The figure, in words

Reaction scheme: 1-methylcyclohexanol in the centre; right arrow labelled conc. H2SO4, heat gives A; left arrow labelled CH3COCl / pyridine gives B. Options give structures for A and B.
  1. (1)A = [figure: methylenecyclohexane] and B = [figure: cyclohexane ring carbon bearing CH3\mathrm{CH_3}, OH and COCH3\mathrm{COCH_3}]
  2. (2)A = [figure: 1-methylcyclohexene] and B = [figure: cyclohexane ring carbon bearing CH3\mathrm{CH_3} and OCOCH3\mathrm{OCOCH_3}]Official answer
  3. (3)A = [figure: 1-methylcyclohexene] and B = [figure: 4-acetyl-1-methylcyclohexan-1-ol (CH3CO\mathrm{CH_3CO} para to the C bearing CH3\mathrm{CH_3} and OH)]
  4. (4)A = [figure: methylenecyclohexane] and B = [figure: cyclohexane ring carbon bearing CH3\mathrm{CH_3} and COCH3\mathrm{COCH_3}]

Official answer

Option 2

NTA final key.

Chapter
Alcohols, Phenols and Ethers
Topic
Alcohols and Phenols
Idea tested
Alcohol Dehydration Ease

Same idea in other shifts

Asked 7× in all
  1. 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
  2. 13 Apr 2023, Shift 1 · Q89For the given reaction CH3−C(CH3)(CH3)−CH(OH)−C(H)(CH3)−CH3→ΔH+\mathrm{CH_3-C(CH_3)(CH_3)-CH(OH)-C(H)(CH_3)-CH_3}\xrightarrow[\Delta]{H^+} (the carbon bearing OH is labelled…MediumNumerical valueHas a figure
  3. 29 Jul 2022, Shift 2 · Q76When enthanol is heated with conc. H2SO4\mathrm{H_2SO_4}, a gas is produced. The compound formed, when this gas is treated with cold dilute…EasySingle correct
  4. 4 Aug 2021, Shift 2 · Q41In the reaction given below, [reaction scheme: drawn structure → A + B, see figure_note] the products A and B formed areMediumDiagram basedHas a figure
  5. 31 Aug 2021, Shift 1 · Q46The major product formed in the following reaction is :MediumDiagram basedHas a figure
  6. 4 Sep 2020, Shift 1 · Q44When neopentyl alcohol is heated with an acid, it slowly converted into an 85 : 15 mixture of alkenes A and B, respectively. What are…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.