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Organic Chemistry – Some Basic Principles and Techniques

JEE Main 2024 (Online) 4th April Morning ShiftMCQEasy📈 Topic in 3% papers+4−1
Ques. 1JEE Main 2024, 4 April (Morning Shift)

Which among the following is incorrect statement?

  1. The electromeric effect is a temporary effect
  2. Hydrogen ion (H+) shows negative electromeric effect
  3. The organic compound shows electromeric effect in the presence of the reagent only.
  4. Electromeric effect dominates over inductive effect

Answer

(2) Hydrogen ion (H+) shows negative electromeric effect

Solution

Electromeric effect: complete transfer of π electrons to one atom of a multiple bond, only on attack of a reagent.

+E: π electrons move to the atom to which the reagent (electrophile) attaches, e.g. H+

−E: π electrons move away from the atom attacked by a nucleophile, e.g. CN-

(A), (C): exists only while the reagent is present ⇒ temporary ⇒ correct

(B): H+ (electrophile) shows +E, not −E ⇒ (B) is incorrect

(D): when the two oppose, the electromeric effect predominates ⇒ correct

Answer: (2)

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

Ques. 2JEE Main 2024, 4 April (Evening Shift)

Correct order of stability of carbanions is : [figure]

  1. d > c > b > a
  2. c > b > d > a
  3. d > a > c > b
  4. a > b > c > d
Ques. 3JEE Main 2024, 4 April (Evening Shift)

The total number of 'sigma' and 'pi' bonds in 2-oxohex-4-ynoic acid is .

Ques. 4JEE Main 2024, 4 April (Evening Shift)

Vanillin compound obtained from vanilla beans, has total sum of oxygen atoms and electrons is .

Ques. 5JEE Main 2024, 1 February (Morning Shift)

Ionic reactions with organic compounds proceed through : Choose the correct answer from the options given below :

  1. (A) only
  2. (B) only
  3. (C) only
  4. (D) and (E) only
Ques. 6JEE Main 2024, 1 February (Evening Shift)

The functional group that shows negative resonance effect is :

  1. -OH
  2. -OR
  3. -COOH
  4. -NH2
Ques. 7JEE Main 2024, 31 January (Morning Shift)

A species having carbon with sextet of electrons and can act as electrophile is called

  1. pentavalent carbon
  2. carbon free radical
  3. carbanion
  4. carbocation
Ques. 8JEE Main 2024, 31 January (Morning Shift)

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

  1. Statement I is incorrect but Statement II is correct.
  2. Statement I is correct but Statement II is incorrect.
  3. Both Statement I and Statement II are correct.
  4. Both Statement I and Statement II are incorrect.
Ques. 9JEE Main 2024, 30 January (Morning Shift)

Which of the following molecule/species is most stable?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 10JEE Main 2024, 30 January (Morning Shift)

Structure of 4-Methylpent-2-enal is :

  1. H2C= H |C- CH3 | H |C-CH2- O \|C-H
  2. CH3-CH2- CH3 |C=CH- O \|C-H
  3. CH3- CH3 |CH-CH=CH- O \|C-H
  4. CH3-CH2-CH= CH3 |C- O \|C-H
Ques. 11JEE Main 2024, 30 January (Evening Shift)

The correct stability order of carbocations is

  1. (CH3)3C > CH3- CH2 > (CH3)2 CH > CH3
  2. (CH3)3 C > (CH3)2 CH > CH3- CH2 > CH3
  3. CH3 > CH3- CH2 > CH3- CH3 | CH > (CH3)3C
  4. CH3 > (CH3)2 CH > CH3- CH2 > (CH3)3 C

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