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Friday, 9 October

JEE Main 2026 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 5 April 2026, Shift 1, Chemistry Q64

Question 64 of 75 in this shift, Chemistry question 14 of 25, Section A.

"P" is a hydrocarbon of molecular formula:- C8H14\mathrm{C_8H_{14}}. On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux condition produces "R", which on treatment with I2\mathrm{I_2}/ NaOH gives a yellow precipitate. Acidification of the solution gives "S". The structure of "S" is given below:- [figure: cyclopentene ring with a CH3_3 group on one double-bond carbon and a COOH group on the other double-bond carbon] The correct structure of "P" is

The figure, in words

Stem figure: structure S, a cyclopentene with CH3 and COOH on the two alkene carbons. Options are alkene structures (cyclohexenes / cyclopentene).
  1. (1)[figure: cyclohexene with CH3_3 substituents at the 1 and 4 positions (para to each other); double bond at the ring bottom right]
  2. (2)[figure: cyclohexene ring bearing a CH2−CH3\mathrm{CH_2-CH_3} (ethyl) group on a double-bond carbon]
  3. (3)[figure: cyclopentene bearing a CH3\mathrm{CH_3} group on one double-bond carbon and a CH2−CH3\mathrm{CH_2-CH_3} group on the other double-bond carbon]
  4. (4)[figure: cyclohexene bearing a CH3\mathrm{CH_3} group on each of the two double-bond carbons (1,2-dimethylcyclohexene)]Official answer

Official answer

Option 4

NTA final key.

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

Same idea in other shifts

Asked 8× 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. 3 Apr 2025, Shift 1 · Q65Which compound would give 3-methyl-6-oxoheptanal upon ozonolysis?MediumDiagram basedHas a figure
  3. 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
  4. 7 Apr 2025, Shift 2 · Q66The number of optically active products obtained from the complete ozonolysis of the given compound is :…MediumOtherHas a figure
  5. 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
  6. 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
  7. 25 Jul 2021, Shift 1 · Q42An Organic compound 'A' C4H8\mathrm{C_4H_8} on treatment with KMnO4/H+\mathrm{KMnO_4/H^+} yields compound 'B' C3H6O\mathrm{C_3H_6O}. Compound 'A'…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.