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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 29 January 2024, Shift 1, Chemistry Q76

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

The final product A formed in the following multistep reaction sequence is

The figure, in words

Reaction scheme: styrene (benzene ring bearing a vinyl group) with reagents (i) H2O, H+ (ii) CrO3 (iii) H2N-NH2, KOH, heating, giving product A.
  1. (1)[figure: ethylbenzene, C6H5CH2CH3\mathrm{C_6H_5CH_2CH_3}]Official answer
  2. (2)[figure: hydrazone of phenylacetaldehyde, C6H5CH2CH=N−NH2\mathrm{C_6H_5CH_2CH=N-NH_2}]
  3. (3)[figure: hydrazone of acetophenone, C6H5C(CH3)=N−NH2\mathrm{C_6H_5C(CH_3)=N-NH_2}]
  4. (4)[figure: phenylacetic acid, C6H5CH2COOH\mathrm{C_6H_5CH_2COOH}]

Official answer

Option 1

NTA final key.

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Alkanes and Free Radicals
Idea tested
Wolff-Kishner Reduction to Alkanes

Same idea in other shifts

Asked 4× in all
  1. 5 Apr 2024, Shift 1 · Q79Identify 'A' in the following reaction : butan-2-one (CH3−C(=O)−CH2−CH3\mathrm{CH_3-C(=O)-CH_2-CH_3})…EasyDiagram basedHas a figure
  2. 11 Apr 2023, Shift 2 · Q77Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : [figure: skeletal…MediumAssertion–reasonHas a figure
  3. 24 Feb 2021, Shift 2 · Q46[Reaction scheme: reactant →?\xrightarrow{?} product] Which of the following reagent is suitable for the preparation of the product in the…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.