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Organic Chemistry – Some Basic Principles and Techniques

JEE Main 2025 (Online) 28th January Morning ShiftMCQEasy📈 Topic in 14% papers+4−1
Ques. 1JEE Main 2025, 28 January (Morning Shift)

The correct order of stability of following carbocations is : [figure]

  1. A > B > C > D
  2. C > B > A > D
  3. B > C > A > D
  4. C > A > B > D

Answer

(4) C > A > B > D

Solution

C is the tropylium (cycloheptatrienyl) cation: planar, cyclic, 6π electrons (4n + 2, n = 1) aromatic; the positive charge is spread over all seven carbons most stable.

A ( Ph3C ): the charge is delocalised into three benzene rings.

B ( Ph2CH ): delocalised into only two rings A > B.

D (sec-butyl cation): a 2° alkyl carbocation stabilised only by +I effect and hyperconjugation least stable.

C > A > B > D

Answer: (4)

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Ques. 2JEE Main 2025, 24 January (Morning Shift)

Which one of the carbocations from the following is most stable?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 3JEE Main 2025, 24 January (Evening Shift)

In the given structure, number of sp and sp2 hybridized carbon atoms present respectively are : [figure]

  1. 3 and 5
  2. 3 and 6
  3. 4 and 5
  4. 4 and 6
Ques. 4JEE Main 2025, 24 January (Evening Shift)

The hydrocarbon (X) with molar mass 80 g mol-1 and 90\% carbon has degree of unsaturation.

Ques. 5JEE Main 2025, 23 January (Morning Shift)

The correct stability order of the following species/molecules is : [figure]

  1. q > r > p
  2. q > p > r
  3. p > q > r
  4. r > q > p
Ques. 6JEE Main 2025, 22 January (Morning Shift)

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

  1. 5-Methoxycarbonyl-2-methylhexanoic acid
  2. Methyl-5-carboxy-2-methylhexanoate.
  3. 2-Carboxy-5-methoxycarbonylhexane.
  4. Methyl-6-carboxy-2,5-dimethylhexanoate.
Ques. 7JEE Main 2025, 22 January (Evening Shift)

The most stable carbocation from the following is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 8JEE Main 2025, 22 January (Evening Shift)

The alkane from below having two secondary hydrogens is :

  1. 2,2,4,5-Tetramethylheptane
  2. 2,2,4,4-Tetramethylhexane
  3. 4-Ethyl-3,4-dimethyloctane
  4. 2,2,3,3-Tetramethylpentane
Ques. 9JEE Main 2024, 9 April (Morning Shift)

Relative stability of the contributing structures is : [figure]

  1. (II) > (I) > (III)
  2. (III) > (II) > (I)
  3. (I) > (III) > (II)
  4. (I) > (II) > (III)
Ques. 10JEE Main 2024, 9 April (Morning Shift)

Correct order of basic strength of Pyrrole, Pyridine and Piperidine is : [figure]

  1. Pyridine > Piperidine > Pyrrole
  2. Pyrrole > Piperidine > Pyridine
  3. Pyrrole > Pyridine > Piperidine
  4. Piperidine > Pyridine > Pyrrole
Ques. 11JEE Main 2024, 9 April (Morning Shift)

How many compounds among the following compounds show inductive, mesomeric as well as hyperconjugation effects? [figure]

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