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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 4 April 2024, Shift 2, Chemistry Q75

Question 75 of 90 in this shift, Chemistry question 15 of 30, Section A.

In the above chemical reaction sequence "A" and "B" respectively are

The figure, in words

Reaction scheme: 1-methylcyclohexene (methyl on the double-bond carbon) --"A"--> open-chain keto-aldehyde CH3-CO-CH2CH2CH2-CHO (aldehyde carbon drawn with H, ketone carbonyl with methyl) --"B"--> the same chain in which the methyl ketone end has become a sodium carboxylate (-COO- Na+) while the CHO group remains.
  1. (1)H2O,H+\mathrm{H_2O, H^+} and KMnO4\mathrm{KMnO_4}
  2. (2)O3,Zn/H2O\mathrm{O_3, Zn/H_2O} and NaOH(alc)/I2\mathrm{NaOH_{(alc)}/I_2}Official answer
  3. (3)H2O,H+\mathrm{H_2O, H^+} and NaOH(alc)/I2\mathrm{NaOH_{(alc)}/I_2}
  4. (4)O3,Zn/H2O\mathrm{O_3, Zn/H_2O} and KMnO4\mathrm{KMnO_4}

Official answer

Option 2

NTA final key.

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Alkenes and Alkynes
Idea tested
Reductive Ozonolysis Products

Same idea in other shifts

Asked 16× in all
  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. 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
  3. 3 Apr 2025, Shift 1 · Q65Which compound would give 3-methyl-6-oxoheptanal upon ozonolysis?MediumDiagram basedHas a figure
  4. 7 Apr 2025, Shift 1 · Q67Given below are two statements: Statement I: Ozonolysis followed by treatment with Zn, H2O\mathrm{H_2O} of cis-2-butene gives ethanal.…MediumTwo statements
  5. 7 Apr 2025, Shift 2 · Q66The number of optically active products obtained from the complete ozonolysis of the given compound is :…MediumOtherHas a figure
  6. 29 Jan 2024, Shift 1 · Q89[figure: trans-2-butene drawn as CH3_3 and H on the left carbon, H and CH3_3 on the right carbon (CH3_3 top-left, H bottom-left, H…EasyNumerical valueHas a figure
  7. 8 Apr 2023, Shift 1 · Q89Molar mass of the hydrocarbon (X) which on ozonolysis consumes one mole of O3\mathrm{O_3} per mole of (X) and gives one mole each of…MediumNumerical value
  8. 25 Jul 2022, Shift 1 · Q73A compound 'A' on reaction with 'X' and 'Y' produces the same major product but different by product 'a' and 'b'. Oxidation of 'a' gives a…MediumSingle correctHas 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.