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Isomerism · Question 14

JEE Main 2025 (Online) 28th January Evening ShiftMCQEasy📈 Topic in 23% papers+4−1
1

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

Answer

(2) Both Statement I and Statement II are true

Solution

Statement I: methylcyclopentane has molecular formula C6H12; hex-3-ene CH3CH2CH=CHCH2CH3 is also C6H12.

Same molecular formula, different structures (ring vs open chain with C=C) they are isomers (ring–chain isomers). Statement I is true.

Statement II: pentan-1-amine CH3(CH2)4NH2 and N-ethylpropan-1-amine CH3CH2-NH-CH2CH2CH3 both have formula C5H13N.

The first contains a primary amino group (-NH2) and the second a secondary amino group (>NH); 1°, 2° and 3° amines of the same formula are treated as functional isomers. Statement II is true.

Answer: (2)

JEE Main 2025 (Online) 28th January Evening Shift

Keep practising — Isomerism

2

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

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 6th April Morning Shift
3

The following structures are : [figure]

  1. enantiomers.
  2. identical molecules.
  3. diastereomers.
  4. meso compounds.
JEE Main 2026 (Online) 4th April Evening Shift
4

Consider the isomers of hydrocarbon with molecular formula C5H10. These isomers do not decolourise KMnO4 solution. These isomers are subjected to chlorination with chlorine in presence of light to give monochloro compounds. The total number of monochloro compounds (structural isomers only) formed is .

JEE Main 2026 (Online) 2nd April Morning Shift
5

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 false
  3. Statement I is true but Statement II is false
  4. Both Statement I and Statement II are true
JEE Main 2026 (Online) 24th January Evening Shift
6

Consider all the structural isomers with molecular formula C5H11Br are separately treated with KOH(aq) to give respective substitution products, without any rearrangement. The number of products which can exhibit optical isomerism from these is .

JEE Main 2026 (Online) 23rd January Morning Shift
7

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

  1. A, B and E only
  2. A, B and C only
  3. C, D and E only
  4. B, C and D only
JEE Main 2026 (Online) 21st January Morning Shift
8

In the light of the above statements, choose the correct answer from the options given below :

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are true
  3. Both Statement I and Statement II are false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 21st January Evening Shift
9

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

  1. A-III, B-I, C-IV, D-II
  2. A-II, B-I, C-IV, D-III
  3. A-I, B-IV, C-III, D-II
  4. A-III, B-I, C-II, D-IV
JEE Main 2026 (Online) 21st January Evening Shift
10

Given below are four compounds : (a) n-propyl chloride (b) isopropyl chloride (c) sec-butyl chloride (d) neopentyl chloride Percentage of carbon in the one which exhibits optical isomerism is :

  1. 46
  2. 40
  3. 52
  4. 56
JEE Main 2026 (Online) 21st January Evening Shift
11

The number of optically active products obtained from the complete ozonolysis of the given compound is : [figure]

  1. 4
  2. 0
  3. 2
  4. 1
JEE Main 2025 (Online) 7th April Evening Shift

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