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Organic Chemistry – Some Basic Principles and Techniques · Question 17

JEE Main 2026 (Online) 24th January Morning ShiftMCQEasy📈 Topic in 10% papers+4−1
1

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

Answer

(4) IV > I > II > V > III

Solution

A benzyl carbanion is stabilised by electron-withdrawing groups and destabilised by electron-donating groups at the para position.

IV: –CHO is a strong –R (–M) group; the negative charge is delocalised up to the carbonyl oxygen most stable.

I: –Br withdraws electrons by –I effect (–I > +R) more stable than unsubstituted II.

II: no substituent (reference).

V: –CH3 donates by +I and hyperconjugation less stable than II.

III: –OCH3 donates strongly by +R effect least stable.

IV > I > II > V > III

Answer: (4)

JEE Main 2026 (Online) 24th January Morning Shift

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

2

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
3

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
4

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
5

From the following, the least stable structure is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 21st January Morning Shift
6

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
7

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
8

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
9

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
10

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
11

In which pairs, the first ion is more stable than the second?

  1. (A) & (B) only
  2. (B) & (D) only
  3. (A) & (C) only
  4. (B) & (C) only
JEE Main 2025 (Online) 4th April Evening Shift

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