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Saturday, 31 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 8 April 2025, Shift 2, Chemistry Q66

Question 66 of 75 in this shift, Chemistry question 16 of 25, Section A.

Choose the correct set of reagents for the following conversion. Ethyl benzene → [structure: p-bromostyrene, i.e. benzene ring with CH=CH2 and Br at para positions]

The figure, in words

Ethyl benzene converted to a para-disubstituted benzene bearing CH=CH2 at the top and Br at the bottom (4-bromostyrene).
  1. (1)Cl2\mathrm{Cl_2}/anhy.AlCl3\mathrm{AlCl_3} ; Br2\mathrm{Br_2}/Fe ; alc. KOH
  2. (2)Br2\mathrm{Br_2}/Fe ; Cl2\mathrm{Cl_2}, Δ ; alc.KOHOfficial answer
  3. (3)Br2\mathrm{Br_2}/anhy.AlCl3\mathrm{AlCl_3} ; Cl2\mathrm{Cl_2}, Δ ; aq. KOH
  4. (4)Cl2\mathrm{Cl_2}/Fe ; Br2\mathrm{Br_2}/anhy.AlCl3\mathrm{AlCl_3} ; aq. KOH

Official answer

Option 2

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
Aromatic Hydrocarbons
Idea tested
Ortho-Para vs Meta Directing

Same idea in other shifts

Asked 11× in all
  1. 2 Apr 2026, Shift 1 · Q66For the given molecule, "xx", the preferred site for the attack of the electrophile is :MediumDiagram basedHas a figure
  2. 1 Feb 2024, Shift 1 · Q88Total number of deactivating groups in aromatic electrophilic substitution reaction among the following is ________.…MediumNumerical valueHas a figure
  3. 1 Feb 2024, Shift 2 · Q74The set of meta directing functional groups from the following sets is :EasySingle correct
  4. 27 Jan 2024, Shift 1 · Q88Among the following, total number of meta directing functional groups is __________. (Integer based)…EasyNumerical value
  5. 24 Jun 2022, Shift 1 · Q73In the given reaction sequence, the major product 'C' is :…MediumSingle correctHas a figure
  6. 26 Jun 2022, Shift 2 · Q74Halogenation of which one of the following will yield m-substituted product with respect to methyl group as a major product?MediumSingle correctHas a figure
  7. 26 Aug 2021, Shift 1 · Q46The correct options for the products A and B of the following reactions are : [figure: hexagonal ring (inner circle) with OH at top; left…MediumDiagram basedHas a figure
  8. 26 Aug 2021, Shift 2 · Q44[reaction scheme] drawn structure --(Br2\mathrm{Br_2} / AlBr3\mathrm{AlBr_3} (C2H5)2O(\mathrm{C_2H_5})_2\mathrm{O})--> ‘A’ (Major Product) Consider…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.