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Organic Chemistry – Some Basic Principles and Techniques

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

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

Answer

(1) (A) & (B) only

Solution

(A) In the first ion the lone pair of –OMe oxygen delocalises onto C (+R), giving a structure in which every atom has an octet ( O=C), while the second has only +I and hyperconjugation of –Me. So the first is more stable. ✓

(B) The first is a carbanion conjugated with the benzene ring bearing an ortho –NO2 group, so the negative charge is delocalised onto the ring and the nitro oxygens (–R, –I) and it is highly stabilised. The second is a carbocation attached to a ring bearing an ortho –NO2 group, whose –R and –I effects destabilise the positive charge. So the first is more stable. ✓

(C) The first is a primary carbocation (only +I / hyperconjugation), while in the second the CH2 is attached to a C=C (allylic carbocation) and is stabilised by resonance. So the second is more stable. ✗

(D) The first is the tert-butyl carbocation (+I and 9 hyperconjugating H), while in the second –OMe on C gives +R stabilisation, which outweighs hyperconjugation. So the second is more stable. ✗

(A) & (B) only.

Answer: (1)

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Ques. 2JEE Main 2025, 4 April (Evening Shift)

The correct order of basicity for the following molecules is : [figure]

  1. R > P > Q
  2. P > Q > R
  3. R > Q > P
  4. Q > P > R
Ques. 3JEE Main 2025, 3 April (Morning Shift)

The least acidic compound, among the following is: [figure]

  1. B
  2. D
  3. A
  4. C
Ques. 4JEE Main 2025, 3 April (Evening Shift)

What is the correct IUPAC name of [figure] ?

  1. 3-Bromo-2-hydroxy-5-nitrobenzoic acid
  2. 2-Hydroxy-3-bromo-5-nitrobenzoic acid
  3. 3-Bromo-4-hydroxy-1-nitrobenzoic acid
  4. 5-Nitro-3-bromo-2-hydroxybenzoic acid
Ques. 5JEE Main 2025, 3 April (Evening Shift)

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 false
  4. Both Statement I and Statement II are true
Ques. 6JEE Main 2025, 2 April (Morning Shift)

Consider the following compound (X) [figure] The most stable and least stable carbon radicals, respectively, produced by homolytic cleavage of corresponding C-H bond are :

  1. III, II
  2. II, IV
  3. I, IV
  4. II, I
Ques. 7JEE 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
Ques. 8JEE 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. 9JEE 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. 10JEE 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. 11JEE 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

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