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Isomerism · Question 2

NEET (UG) 2026MCQEasy📈 Topic in 25% papers+4−1
1

The pair of molecules that are metamers among the following is :

  1. CH3OCH2CH2CH3 and CH3CH2OCH2CH3
  2. CH3CH2CH2OH and CH3-CH(OH)-CH3
  3. CH3CH2CH2CH2CH3 and (CH3)2CHCH2CH3
  4. [figure] and [figure]

Answer

(1) CH3OCH2CH2CH3 and CH3CH2OCH2CH3

Solution

As per NCERT, metamerism arises due to different alkyl chains on either side of the same functional group.

CH3-O-CH2CH2CH3 (methyl propyl ether) and C2H5-O-C2H5 (diethyl ether): same formula C4H10O, same –O– group, different alkyl groups ⇒ metamers.

Other pairs: propan-1-ol/propan-2-ol (position isomers), pentane/2-methylbutane (chain isomers), propanone/propanal (functional isomers).

Answer: (1)

NEET (UG) 2026

Keep practising — Isomerism

2

How many products (including stereoisomers) are expected from monochlorination of the following compound? [figure]

  1. 5
  2. 6
  3. 2
  4. 3
NEET (UG) 2025
3

Total number of possible isomers (both structural as well as stereoisomers) of cyclic ethers of molecular formula C4H8O is :

  1. 10
  2. 11
  3. 6
  4. 8
NEET (UG) 2025
4

Which one of the following compounds can exist as cis-trans isomers?

  1. 1,1-Dimethylcyclopropane
  2. 1,2-Dimethylcyclohexane
  3. Pent-1-ene
  4. 2-Methylhex-2-ene
NEET (UG) 2025
5

The incorrect statement regarding chirality is

  1. SN1 reaction yields 1 : 1 mixture of both enantiomers
  2. The product obtained by SN2 reaction of haloalkane having chirality at the reactive site shows inversion of configuration
  3. Enantiomers are superimposable mirror images on each other
  4. A racemic mixture shows zero optical rotation
NEET (UG) 2022
6

The compound which shows metamerism is :

  1. C4H10O
  2. C5H12
  3. C3H8O
  4. C3H6O
NEET (UG) 2021
7

Dihedral angle of least stable conformer of ethane is :

  1. 0
  2. 120
  3. 180
  4. 60
NEET (UG) 2021
8

With respect to the conformers of ethane, which of the following statements is true?

  1. Bond angle changes but bond length remains same.
  2. Both bond angle and bond length change.
  3. Both bond angle and bond length remain same.
  4. Bond angle remains same but bond length changes.
NEET 2017
9

Which of the following biphenyls is optically active ?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 1)
10

The correct statement regarding the comparison of staggered and eclipsed conformations of ethane, is

  1. the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain
  2. the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain
  3. the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has torsional strain
  4. the eclipsed conformation of ethane is more stable than staggered conformation, because eclipsed conformation has no torsional strain.
NEET 2016 (Phase 1)
11

The correct statement regarding a carbonyl compound with a hydrogen atom on its alpha-carbon, is

  1. a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as carbonylation
  2. a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as keto-enol tautomerism
  3. a carbonyl compound with a hydrogen atom on its alpha-carbon never equilibrates with its corresponding enol
  4. a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as aldehyde-ketone equilibration.
NEET 2016 (Phase 1)

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