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Friday, 9 October

JEE Main 2022 · ChemistryMultiple choiceOtherHardMulti-step

JEE Main 29 June 2022, Shift 1, Chemistry Q74

Question 74 of 90 in this shift, Chemistry question 14 of 30, Section A.

[reaction scheme: 2-bromophenol →(CH3)3CLi\xrightarrow{(\mathrm{CH_3})_3\mathrm{CLi}} [A] →(i) CO2, (ii) H3O+\xrightarrow{\text{(i) } \mathrm{CO_2}\text{, (ii) } \mathrm{H_3O^+}} salicylic acid (2-hydroxybenzoic acid)] In the given conversion the compound A is :

The figure, in words

Reaction scheme: benzene ring bearing Br and OH on adjacent carbons (2-bromophenol) reacting with (CH3)3CLi to give [A]; then (i) CO2, (ii) H3O+ gives salicylic acid (ring with COOH ortho to OH). Options are structures of A.
  1. (1)[figure: benzene ring with Li ortho to OH, i.e. 2-lithiophenol]
  2. (2)[figure: benzene ring with Li ortho to OLi, i.e. 2-lithiophenoxide (lithium 2-lithiophenolate)]Official answer
  3. (3)[figure: benzene ring with Br ortho to OC(CH3)3\mathrm{OC(CH_3)_3}, i.e. 2-bromophenyl tert-butyl ether]
  4. (4)[figure: benzene ring with C(CH3)3\mathrm{C(CH_3)_3} ortho to OH, i.e. 2-tert-butylphenol]

Official answer

Option 2

NTA final key (2022 Session 1).

Chapter
Haloalkanes and Haloarenes
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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.