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Saturday, 31 October

JEE Main 2017 · ChemistryMultiple choiceSingle correctHardMulti-step

JEE Main 2 April 2017 (offline), Chemistry Q52

Question 52 of 90 in this shift, Chemistry question 22 of 30.

Which of the following, upon treatment with *tert*-BuONa followed by addition of bromine water, fails to decolourize the colour of bromine ?

The figure, in words

Options are drawn skeletal structures with a bromine substituent.
  1. (1)[structure: phenyl ether C6H5−O−CH(CH3)Br\mathrm{C_6H_5-O-CH(CH_3)Br}]
  2. (2)[structure: cyclohexyl ketone, cyclohexyl-C(=O)CH(CH3)Br\mathrm{C(=O)CH(CH_3)Br}]
  3. (3)[structure: cyclohexyl ether, cyclohexyl-O−CH2Br\mathrm{O-CH_2Br}]Official answer
  4. (4)[structure: C6H5−CH2−CH(Br)−C6H5\mathrm{C_6H_5-CH_2-CH(Br)-C_6H_5}]

Official answer

Option 3

CBSE answer key (25/04/2017, used for result).

Chapter
Haloalkanes and Haloarenes
Topic
Alkenes and Alkynes
Idea tested
Saytzeff vs. Hofmann Elimination

Same idea in other shifts

Asked 7× in all
  1. 2 Apr 2025, Shift 2 · Q75Consider the above sequence of reactions. 151 g of 2-bromopentane is made to react. Yield of major product P is 80% whereas Q is 100%.…MediumNumerical valueHas a figure
  2. 5 Apr 2024, Shift 2 · Q77Identify the major product in the following reaction. 1-bromo-1-methylcyclopentane…EasyDiagram basedHas a figure
  3. 25 Jun 2022, Shift 1 · Q75The major product in the reaction [figure: CH3−C(CH3)(CH3)−Cl\mathrm{CH_3-C(CH_3)(CH_3)-Cl} (central C with CH3\mathrm{CH_3} above, CH3\mathrm{CH_3} below,…EasySingle correctHas a figure
  4. 31 Aug 2021, Shift 2 · Q41The major product of the following reaction is : [reaction: starting material drawn as a five-membered ring; reagent above/below arrow:…MediumDiagram basedHas a figure
  5. 2 Sep 2020, Shift 2 · Q44The major product obtained from E2\mathrm{E_2}-elimination of 3-bromo-2-fluoropentane is :HardSingle correctHas a figure
  6. 2 Apr 2017 (offline) · Q56The major product obtained in the following reaction is : [reaction: (+)-C6H5CH(Br)CH2C6H5\mathrm{C_6H_5CH(Br)CH_2C_6H_5} (Br on wedge, H on hash at the…MediumSingle correctHas a figure

Question text from the official JEE Main paper published by NTA (CBSE ran the 2017 exam); 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.