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Organic Chemistry – Some Basic Principles and Techniques · Question 16

JEE Main 2026 (Online) 24th January Morning ShiftMCQEasy📈 Topic in 6% papers+4−1
1

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

Answer

(3) I > III > II > IV

Solution

Stability of alkenes increases with the number of α-hydrogens (hyperconjugation) / alkyl groups on the C=C carbons:

I: 2,3-dimethylbut-2-ene, tetrasubstituted, 12 α-H

III: 2-methylbut-2-ene, trisubstituted, 9 α-H

II: trans-but-2-ene, disubstituted, 6 α-H

IV: cis-but-2-ene, disubstituted, 6 α-H

I > III > (II, IV)

Between II and IV: in the cis isomer the two CH3 groups are on the same side and repel each other (steric strain), so the trans isomer is more stable (lower heat of hydrogenation).

I > III > II > IV

Answer: (3)

JEE Main 2026 (Online) 24th January Morning Shift

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

2

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
3

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
4

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
5

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
6

From the following, the least stable structure is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 21st January Morning Shift
7

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
8

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
9

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
10

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

  1. Both Statement I and Statement II are true
  2. Statement I is true but Statement II is false
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are false
JEE Main 2025 (Online) 4th April Morning Shift
11

The IUPAC name of the following compound is: HC C-CH2- OH |CH-CH2-CH=CH2

  1. 4-Hydroxyhept-6-en-1-yne
  2. Hept-1-en-6-yn-4-ol
  3. Hept-6-en-1-yn-4-ol
  4. 4-Hydroxyhept-1-en-6-yne
JEE Main 2025 (Online) 4th April Evening Shift

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