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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceOtherEasyApplication

JEE Main 4 April 2024, Shift 1, Chemistry Q79

Question 79 of 90 in this shift, Chemistry question 19 of 30, Section A.

Identify the product in the following reaction : [reactant: benzene ring with a CHO group and, meta to it, a COCH3 group (3-acetylbenzaldehyde)] →HClZn−Hg\xrightarrow[\mathrm{HCl}]{\mathrm{Zn-Hg}} Product

The figure, in words

Reactant: benzene ring bearing a CHO group and, meta to it, an acetyl (COCH3) group; reagent Zn-Hg/HCl. Options are four drawn products.
  1. (1)[structure: benzene ring with CH3 and CH2CH3 groups meta to each other (3-ethyltoluene)]Official answer
  2. (2)[structure: benzene ring with CH3 and COCH3 groups meta to each other (3-methylacetophenone)]
  3. (3)[structure: benzene ring with CH2OH and COCH3 groups meta to each other]
  4. (4)[structure: benzene ring with CH2OH and CH(OH)CH3 groups meta to each other]

Official answer

Option 1

NTA final key.

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Alkanes and Free Radicals
Idea tested
Clemmensen Reduction to Alkanes

Same idea in other shifts

Asked 3× in all
  1. 11 Apr 2023, Shift 2 · Q76The major product formed in the following reaction is C6H5−CH(OH)−CH(CH3)−CH2CHO\mathrm{C_6H_5-CH(OH)-CH(CH_3)-CH_2CHO}…MediumOtherHas a figure
  2. 25 Jul 2022, Shift 2 · Q76CH3−CH2−CN\mathrm{CH_3-CH_2-CN} --(CH3MgBr\mathrm{CH_3MgBr}, Ether)--> A --(H3O+\mathrm{H_3O^+})--> B --(Zn-Hg, HCl)--> C The correct structure of C isMediumOther

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.