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Saturday, 31 October

JEE Main 2023 · ChemistryMultiple choiceOtherHardConceptual

JEE Main 10 April 2023, Shift 2, Chemistry Q73

Question 73 of 90 in this shift, Chemistry question 13 of 30, Section A.

The decreasing order of hydride affinity for following carbocations is: A. CH2=CH−C+(CH3)−CH3\mathrm{CH_2=CH-\overset{+}{C}(CH_3)-CH_3} (carbocation carbon bearing vinyl and two methyl groups) B. C6H5−C+(C6H5)−C6H5\mathrm{C_6H_5-\overset{+}{C}(C_6H_5)-C_6H_5} (triphenylmethyl cation) C. H3C−C+(CH3)−CH3\mathrm{H_3C-\overset{+}{C}(CH_3)-CH_3} (tert-butyl cation) D. cation carbon bearing three cyclopropyl rings (tricyclopropylmethyl cation) Choose the correct answer from the options given below:

The figure, in words

Four carbocations drawn as structures: A CH2=CH-C(+)(CH3)-CH3 (allyl-type, with CH3 on the right and CH3 below the C+); B (C6H5)3C+; C (CH3)3C+; D carbon cation attached to three cyclopropyl rings.
  1. (1)C, A, B, DOfficial answer
  2. (2)A, C, B, D
  3. (3)A, C, D, B
  4. (4)C, A, D, B

Official answer

Option 1

NTA final key.

Chapter
Organic Chemistry: Some Basic Principles and Techniques
Topic
Inductive and Electromeric Effects
Idea tested
Carbocation Stability

Same idea in other shifts

Asked 4× in all
  1. 4 Apr 2025, Shift 2 · Q63In which pairs, the first ion is more stable than the second ? (A) [figure: 1-methoxycyclohexyl cation] & [figure: 1-methylcyclohexyl…MediumOtherHas a figure
  2. 30 Jan 2024, Shift 2 · Q73The correct stability order of carbocations isEasySingle correct
  3. 24 Jun 2022, Shift 2 · Q73Arrange the following carbocations in decreasing order of stability.HardDiagram 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.