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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 26 February 2021, Shift 1, Chemistry Q45

Question 45 of 90 in this shift, Chemistry question 15 of 30, Section A.

Identify the major products A and B respectively in the following reactions of phenol : [reaction scheme, see figure_note]

The figure, in words

Stem scheme as drawn: central ring with inner circle and OH on top vertex; left arrow labelled (i) CHCl3, NaOH / (ii) H3O+ leading to circled B; right arrow labelled Br2 in CS2 / 273 K leading to circled A. Options are pairs of ring structures as described in each option.
  1. (1)[figure: ring with inner circle, OH on top vertex, Br on upper-right vertex] and [figure: ring with inner circle, OH on top vertex, CHO on upper-right vertex]
  2. (2)[figure: ring with inner circle, OH on top vertex, Br on bottom vertex] and [figure: ring with inner circle, OH on top vertex, CHO on bottom vertex]
  3. (3)[figure: ring with inner circle, OH on top vertex, Br on upper-right vertex] and [figure: ring with inner circle, OH on top vertex, CHO on bottom vertex]
  4. (4)[figure: ring with inner circle, OH on top vertex, Br on bottom vertex] and [figure: ring with inner circle, OH on top vertex, CHO on upper-right vertex]Official answer

Official answer

Option 4

NTA final key.

Chapter
Alcohols, Phenols and Ethers
Topic
Alcohols and Phenols
Idea tested
Reimer-Tiemann Reaction

Same idea in other shifts

Asked 9× in all
  1. 6 Apr 2024, Shift 1 · Q78In Reimer - Tiemann reaction, phenol is converted into salicylaldehyde through an intermediate. The structure of intermediate is __________.EasyDiagram basedHas a figure
  2. 8 Apr 2024, Shift 2 · Q77Match List - I with List - II. List - I (Reactions) | List - II (Products) (A) aniline (C6H5NH2\mathrm{C_6H_5NH_2}) with (i)…MediumMatch the listHas a figure
  3. 30 Jan 2024, Shift 2 · Q76Salicylaldehyde is synthesized from phenol, when reacted withEasySingle correct
  4. 25 Jun 2022, Shift 1 · Q76The intermediate X, in the reaction : [figure: CHCl3\mathrm{CHCl_3} + Aq. NaOH + benzene ring with OH substituent, arrow to [X]; below [X] an…EasyDiagram basedHas a figure
  5. 27 Jun 2022, Shift 2 · Q75Match List I with List II. List I | List II A. [drawn: benzene ring bearing OH →\rightarrow benzene ring bearing OH and, on a…MediumMatch the listHas a figure
  6. 4 Aug 2021, Shift 1 · Q46Match List I with List II List I List II A. Kolbe's Reaction I. [structure: benzene ring with a CHO substituent] B. Gatterman-Koch…MediumMatch the listHas a figure
  7. 22 Jul 2021, Shift 2 · Q45An organic compound A (C6H6O\mathrm{C_6H_6O}) gives dark green colouration with ferric chloride. On treatment with CHCl3\mathrm{CHCl_3} and KOH,…MediumDiagram basedHas a figure
  8. 6 Sep 2020, Shift 2 · Q50A solution of phenol in chloroform when treated with aqueous NaOH gives compound P as a major product. The mass percentage of carbon in P…EasyNumerical 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.