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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 31 January 2024, Shift 2, Chemistry Q76

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

Identify A and B in the following reaction sequence. [reaction: bromobenzene --(Conc HNO3_3)--> A --((i) NaOH, (ii) HCl)--> B]

The figure, in words

Reaction scheme: bromobenzene with conc. HNO3 gives A; A with (i) NaOH then (ii) HCl gives B. Options are structure pairs A and B.
  1. (1)[figure: A = 1-bromo-4-nitrobenzene (Br and NO2 para); B = benzene ring with Br at position 1, OH at position 2 and NO2 at position 4]
  2. (2)[figure: A = 1-bromo-2,4-dinitrobenzene (Br at 1, NO2 at 2 and 4); B = benzene ring with Br at 1, OH at 2 and OH at 4]
  3. (3)[figure: A = 2-bromo-1,3,5-trinitrobenzene (Br flanked by two ortho NO2, para NO2); B = 2,4,6-trinitrophenol (OH flanked by two ortho NO2, para NO2)]Official answer
  4. (4)[figure: A = nitrobenzene; B = 3-nitrophenol (NO2 and OH meta)]

Official answer

Option 3

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
Aromatic Hydrocarbons
Idea tested
SNAr and Meisenheimer Complex

Same idea in other shifts

Asked 5× in all
  1. 8 Apr 2023, Shift 2 · Q73The correct order of reactivity of following haloarenes towards nucleophilic substitution with aqueous NaOH is : A. [chlorobenzene] B.…MediumSingle correctHas a figure
  2. 3 Aug 2021, Shift 1 · Q44The correct arrangement of the following compounds in the order of increasing difficulty towards nucleophilic substitution isMediumDiagram basedHas a figure
  3. 3 Aug 2021, Shift 2 · Q43Order of reactivity for hydrolysis of substituted chlorobenzenes in the presence of aqueous NaOH isMediumSingle correctHas a figure
  4. 24 Feb 2021, Shift 2 · Q45The correct order of the following compounds showing increasing tendency towards nucleophilic substitution reaction is : (i) [figure:…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.