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Isomerism

JEE Main 2025 (Online) 7th April Evening ShiftMCQMedium📈 Topic in 7% papers+4−1
Ques. 1JEE Main 2025, 7 April (Evening Shift)

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

  1. Both Statement I and Statement II are correct
  2. Statement I is incorrect but Statement II is correct
  3. Both Statement I and Statement II are incorrect
  4. Statement I is correct but Statement II is incorrect

Answer

(4) Statement I is correct but Statement II is incorrect

Solution

Statement I: In cis-1,2-dihaloethenes the two C–X bond moments add up. Cl is more electronegative than Br, so the C–Cl bond moment is larger.

cis-1,2-dichloroethene (μ ≈ 1.90 D) is more polar than cis-1,2-dibromoethene (μ ≈ 1.35 D). Correct.

Statement II: As per NCERT, cis isomers have higher boiling points than trans isomers (stronger dipole–dipole forces), so the boiling point of trans-1,2-dibromoethene is lower than that of the cis isomer — this part is true. But in the trans isomer the two C–Br bond moments cancel (μ = 0), so it is less polar, not more polar, than the cis isomer. Incorrect.

Statement I is correct but Statement II is incorrect.

Answer: (4)

Keep practising — Isomerism

Ques. 2JEE Main 2025, 3 April (Morning Shift)

Identify the correct statements from the following. Choose the correct answer from the options given below:

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

The total number of structural isomers possible for the substituted benzene derivatives with the molecular formula C9H12 is .

Ques. 4JEE Main 2025, 28 January (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. Both Statement I and Statement II are true
  3. Statement I is true but Statement II is false
  4. Both Statement I and Statement II are false
Ques. 5JEE Main 2025, 24 January (Evening Shift)

The possible number of stereoisomers for 5-phenylpent-4-en-2-ol is .

Ques. 6JEE Main 2025, 22 January (Morning Shift)

How many different stereoisomers are possible for the given molecule? [figure]

  1. 2
  2. 1
  3. 3
  4. 4
Ques. 7JEE Main 2025, 22 January (Morning Shift)

The incorrect statements regarding geometrical isomerism are : Choose the correct answer from the options given below :

  1. A and E Only
  2. A, D and E Only
  3. C, D and E Only
  4. B and C Only
Ques. 8JEE Main 2024, 9 April (Evening Shift)

Total number of stereo isomers possible for the given structure : [figure]

  1. 4
  2. 2
  3. 8
  4. 3
Ques. 9JEE Main 2024, 8 April (Morning Shift)

The number of optical isomers in following compound is : . [figure]

Ques. 10JEE Main 2024, 8 April (Evening Shift)

The number of optically active compounds from the following is . [figure] CH3-CH2-CH2-CH2-OH, CH3-CH2- Cl |CH-CH3, CH3-CH2-CH2-CH2-Cl, (CH3)2CH-CH2-CH2-Cl

Ques. 11JEE Main 2024, 6 April (Morning Shift)

Which of the following is metamer of the given compound (X) ? [figure]

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

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