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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 8 January 2020, Shift 2, Chemistry Q42

Question 42 of 75 in this shift, Chemistry question 17 of 25, Section A.

An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation, and also gives following reaction : X →Zn/H2OO3 A →[Ag(NH3)2]+\mathrm{X\ \xrightarrow[Zn/H_2O]{O_3}\ A\ \xrightarrow{[Ag(NH_3)_2]^+}} B(3-oxo-hexanedicarboxylic acid) X will be :

The figure, in words

Reaction scheme drawn: X --(O3 over Zn/H2O)--> A --([Ag(NH3)2]+)--> B(3-oxo-hexanedicarboxylic acid).
  1. (1)[figure: six-membered ring; double bond to a carbon outside the ring at the top ring atom; one ring double bond on the right side of the ring]
  2. (2)[figure: six-membered ring; top ring atom carries a double-bonded O; one ring double bond on the right side of the ring]
  3. (3)[figure: six-membered ring; double bond to a carbon outside the ring at the upper left ring atom; one ring double bond on the right side of the ring]Official answer
  4. (4)[figure: six-membered ring with no ring double bond; two double bonds to carbons outside the ring, one at the top ring atom and one at the lower left ring atom]

Official answer

Option 3

NTA final key (Jan 2020).

Chapter
Hydrocarbons
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. 4 Apr 2024, Shift 2 · Q75In the above chemical reaction sequence "A" and "B" respectively areMediumDiagram basedHas a figure
  7. 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
  8. 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

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.