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Friday, 9 October

JEE Main 2024 · ChemistryMultiple choiceSingle correctEasyApplication

JEE Main 9 April 2024, Shift 1, Chemistry Q76

Question 76 of 90 in this shift, Chemistry question 16 of 30, Section A.

Identify the product A and product B in the following set of reactions. [figure: CH3−CH=CH2\mathrm{CH_3-CH=CH_2} →H2O, H+\xrightarrow{\mathrm{H_2O,\ H^+}} major Product A; CH3−CH=CH2\mathrm{CH_3-CH=CH_2} →H2O, H2O2, O‾H(BH3)2\xrightarrow[\mathrm{H_2O,\ H_2O_2,\ \overline{O}H}]{\mathrm{(BH_3)_2}} major Product B]

The figure, in words

Propene with two reaction paths: H2O/H+ gives product A; (BH3)2 then H2O, H2O2, OH- gives product B.
  1. (1)A - CH3CH2CH2−OH\mathrm{CH_3CH_2CH_2-OH} B - CH3CH2CH2−OH\mathrm{CH_3CH_2CH_2-OH}
  2. (2)A - CH3−CH(OH)−CH3\mathrm{CH_3-CH(OH)-CH_3} B - CH3CH2CH2−OH\mathrm{CH_3CH_2CH_2-OH}Official answer
  3. (3)A - CH3CH2CH2−OH\mathrm{CH_3CH_2CH_2-OH} B - CH3CH(OH)−CH3\mathrm{CH_3CH(OH)-CH_3}
  4. (4)A - CH3CH2CH3\mathrm{CH_3CH_2CH_3} B - CH3CH2CH3\mathrm{CH_3CH_2CH_3}

Official answer

Option 2

NTA final key.

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

Same topic in other shifts

All Alkenes and Alkynes questions
  1. 4 Apr 2026, Shift 1 · Q64An alkene (X) on ozonolysis followed by reduction gives following products. H−CHO\mathrm{H-CHO} (2 moles), OHC−CO−CHO\mathrm{OHC-CO-CHO}…HardDiagram basedHas a figure
  2. 4 Apr 2026, Shift 2 · Q64Compound (X) is subjected to the sequence of reactions as shown above. Molar mass of the major product (Y) formed is ________…MediumDiagram basedHas a figure
  3. 5 Apr 2026, Shift 1 · Q64"P" is a hydrocarbon of molecular formula:- C8H14\mathrm{C_8H_{14}}. On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux…HardDiagram basedHas a figure
  4. 6 Apr 2026, Shift 1 · Q66Given below are two statements: Statement I: 3-phenylpropene reacts with HBr and gives secondary alkyl bromide having a chiral carbon atom…MediumTwo statements
  5. 6 Apr 2026, Shift 2 · Q65An optically active alkyl bromide C4H9Br\mathrm{C_4H_9Br}, reacts with ethanolic KOH to form major compound [A] which reacts with bromine to…MediumSingle correct
  6. 2 Apr 2025, Shift 1 · Q66An optically active alkyl halide C4H9Br\mathrm{C_4H_9Br} [A] reacts with hot KOH dissolved in ethanol and forms alkene [B] as major product…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.