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Organic Chemistry – Some Basic Principles and Techniques · Question 14

JEE Main 2026 (Online) 28th January Morning ShiftMCQEasy📈 Topic in 10% papers+4−1
1

CORRECT order of stability for the following is CH2=CH-, CH3-CH2-, CH C-

  1. CH C- > CH3-CH2- > CH2=CH-
  2. CH2=CH- > CH C- > CH3-CH2-
  3. CH C- > CH2=CH- > CH3-CH2-
  4. CH3-CH2- > CH2=CH- > CH C-

Answer

(3) CH C- > CH2=CH- > CH3-CH2-

Solution

The stability of a carbanion increases with the s-character of the orbital holding the lone pair, because an orbital with more s-character keeps the electron pair closer to the nucleus (higher electronegativity of carbon).

CH C-: sp (50 % s) > CH2=CH-: sp2 (33 % s) > CH3-CH2-: sp3 (25 % s)

In addition, the ethyl carbanion is destabilised by the +I effect of the methyl group.

Stability: CH C- > CH2=CH- > CH3-CH2-

(This is also the order of acidity of the parent hydrocarbons: ethyne > ethene > ethane.)

Answer: (3)

JEE Main 2026 (Online) 28th January Morning Shift

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

2

The cyclic cations having the same number of hyperconjugation are : Choose the correct answer from the options given below :

  1. B and C Only
  2. A and B Only
  3. A and C Only
  4. A, C and D Only
JEE Main 2026 (Online) 28th January Evening Shift
3

Arrange the following alkenes in decreasing order of stability. [figure] Choose the correct answer from the options given below:

  1. III > I > II > IV
  2. III > II > I > IV
  3. I > III > II > IV
  4. I > III > IV > II
JEE Main 2026 (Online) 24th January Morning Shift
4

Arrange the following carbanions in the decreasing order of stability. I. p-Br-C6H4- CH2 II. C6H5- CH2 III. p-CH3O-C6H4- CH2 IV. p-CHO-C6H4- CH2 V. p-CH3-C6H4- CH2 Choose the correct answer from the options given below :

  1. I > II > IV > V > III
  2. IV > II > I > III > V
  3. I > IV > II > V > III
  4. IV > I > II > V > III
JEE Main 2026 (Online) 24th January Morning Shift
5

Find out the statements which are not true. Choose the correct answer from the options given below :

  1. A, D & E only
  2. A, C & D only
  3. B & D only
  4. B, D & E only
JEE Main 2026 (Online) 24th January Evening Shift
6

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

  1. Statement I is false but Statement II is true
  2. Statement I is true but Statement II is false
  3. Both Statement I and Statement II are true
  4. Both Statement I and Statement II are false
JEE Main 2026 (Online) 23rd January Evening Shift
7

The IUPAC name of the following compound is : [figure]

  1. 2-bromo-5-methylhexylpropanoate
  2. n-propyl-1-bromo-4-methylhexanoate
  3. n-propyl-2-bromo-5-methylheptanoate
  4. 2-bromo-5-methylpropanoate
JEE Main 2026 (Online) 22nd January Evening Shift
8

From the following, the least stable structure is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 21st January Morning Shift
9

Match the LIST-I with LIST-II Choose the correct answer from the options given below:

  1. A-IV, B-II, C-III, D-I
  2. A-II, B-III, C-I, D-IV
  3. A-III, B-IV, C-I, D-II
  4. A-III, B-IV, C-II, D-I
JEE Main 2025 (Online) 8th April Evening Shift
10

What is the correct IUPAC name of the compound? [figure]

  1. 1-Ethylcyclopent-2-en-3-ol
  2. 4-Ethylcyclopent-2-en-1-ol
  3. 1-Ethyl-3-hydroxycyclopent-2-ene
  4. 4-Ethyl-1-hydroxycyclopent-2-ene
JEE Main 2025 (Online) 8th April Evening Shift
11

Which of the following is the correct IUPAC name of given organic compound (X)? [figure]

  1. 4-Bromo-3-methylbut-2-ene
  2. 1-Bromo-2-methylbut-2-ene
  3. 3-Bromo-3-methylprop-2-ene
  4. 2-Bromo-2-methylbut-2-ene
JEE Main 2025 (Online) 7th April Morning Shift

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