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Organic Chemistry – Some Basic Principles and Techniques

JEE Main 2025 (Online) 2nd April Morning ShiftMCQMedium📈 Topic in 14% papers+4−1
Ques. 1JEE Main 2025, 2 April (Morning Shift)

Designate whether each of the following compounds is aromatic or not aromatic. [figure]

  1. a, c, d, e, h aromatic and b, f, g not aromatic
  2. b, e, f, g aromatic and a, c, d, h not aromatic
  3. a, b, c, d aromatic and e, f, g, h not aromatic
  4. e, g aromatic and a, b, c, d, f, h not aromatic

Answer

(1) a, c, d, e, h aromatic and b, f, g not aromatic

Solution

A species is aromatic if it is cyclic, planar, fully conjugated and has (4n+2) π electrons (Hückel rule).

(a) cyclopentadienyl anion: 4 π + lone pair in conjugation = 6 π (n = 1) aromatic

(b) cyclopentadienyl cation: 4 π (4n) not aromatic (antiaromatic)

(c) cyclobutadienyl dication: 2 π (n = 0) aromatic

(d) cyclobutadienyl dianion: 2 π + 4 electrons of the two carbanions = 6 π aromatic

(e) cycloheptatrienyl (tropylium) cation: 6 π aromatic

(f) cyclooctatetraene: 8 π, tub-shaped (non-planar) not aromatic

(g) cyclobutadiene: 4 π not aromatic (antiaromatic)

(h) cyclopropenyl cation: 2 π aromatic

a, c, d, e, h are aromatic and b, f, g are not aromatic.

Answer: (1)

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Ques. 2JEE Main 2025, 2 April (Evening Shift)

In 3,3-dimethylhex-1-en-4-yne, there are sp3, sp2 and sp hybridised carbon atoms respectively.

  1. 4, 2, 2
  2. 2, 4, 2
  3. 3, 3, 2
  4. 2, 2, 4
Ques. 3JEE Main 2025, 29 January (Morning Shift)

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

  1. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
  2. (A)-(II), (B)-(III), (C)-(I), (D)-(IV)
  3. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
  4. (A)-(III), (B)-(II), (C)-(I), (D)-(IV)
Ques. 4JEE Main 2025, 29 January (Morning Shift)

Total number of nucleophiles from the following is : NH3, PhSH, (H3C)2S, H2C=CH2, OH, H3O , (CH3)2 CO, [figure]

  1. 4
  2. 6
  3. 5
  4. 7
Ques. 5JEE Main 2025, 29 January (Evening Shift)

Total number of sigma ( ) and pi( ) bonds respectively present in hex-1-en-4-yne are:

  1. 14 and 3
  2. 11 and 3
  3. 13 and 3
  4. 3 and 13
Ques. 6JEE 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
Ques. 7JEE 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. 8JEE 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. 9JEE Main 2025, 24 January (Evening Shift)

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

Ques. 10JEE 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. 11JEE 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.

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