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Organic Chemistry – Some Basic Principles and Techniques

JEE Main 2025 (Online) 23rd January Morning ShiftMCQMedium📈 Topic in 8% papers+4−1
Ques. 1JEE 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

Answer

(1) q > r > p

Solution

Concept: Hückel rule: (4n+2) e⁻ planar ring ⇒ aromatic (stable); 4n ⇒ antiaromatic (unstable); non-planar ⇒ non-aromatic.

p: 4 π e⁻ ⇒ antiaromatic (least stable)

q: 6 π e⁻ ⇒ aromatic (most stable)

r: 8 π e⁻ but tub-shaped ⇒ non-aromatic

∴ q > r > p

Answer: (1)

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Ques. 2JEE 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. 3JEE Main 2025, 22 January (Evening Shift)

The most stable carbocation from the following is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 4JEE 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

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