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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 4 September 2020, Shift 1, Chemistry Q43

Question 43 of 75 in this shift, Chemistry question 18 of 25.

[P] on treatment with Br2/FeBr3\mathrm{Br_2/FeBr_3} in CCl4\mathrm{CCl_4} produced a single isomer C8H7O2Br\mathrm{C_8H_7O_2Br} while heating [P] with sodalime gave toluene. The compound [P] is :

The figure, in words

All four options are hexagons with an inner circle and the substituents as stated.
  1. (1)[figure: hexagon with an inner circle with CH2COOH printed above a vertical bond to the top vertex]
  2. (2)[figure: hexagon with an inner circle with COOH on the top vertex and CH3 on the next vertex (upper right)]
  3. (3)[figure: hexagon with an inner circle with COOH on the top vertex and CH3 on the lower-right vertex]
  4. (4)[figure: hexagon with an inner circle with COOH on the top vertex and CH3 on the bottom vertex]Official answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Carboxylic Acids and Derivatives
Idea tested
Decarboxylation Reactions

Same idea in other shifts

Asked 2× in all
  1. 24 Jun 2022, Shift 2 · Q76Hex-4-ene-2-ol on treatment with PCC gives 'A'. 'A' on reaction with sodium hypoiodite gives 'B', which on further heating with soda lime…MediumSingle correct

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.