Isomerism

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]

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

1. 5
2. 6
3. 2
4. 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

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

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

The compound which shows metamerism is :

1. C4H10O
2. C5H12
3. C3H8O
4. C3H6O

Dihedral angle of least stable conformer of ethane is :

1. 0
2. 120
3. 180
4. 60

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.

Which of the following biphenyls is optically active ?

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

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.

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.

Which among the given molecules can exhibit tautomerism? [figure]

1. III only
2. Both I and III
3. Both I and II
4. Both II and III

The possible stereo-structures of CH3CHOHCOOH, which are optically active, are called

1. atropisomers
2. enantiomers
3. mesomers
4. diastereomers

In an SN1 reaction on chiral centers, there is

1. inversion more than retention leading to partial racemisation
2. 100% retention
3. 100% inversion
4. 100% racemisation

The number of structural isomers possible from the molecular formula C3H9N is

1. 5
2. 2
3. 3
4. 4

Given : [figure] Which of the given compounds can exhibit tautomerism?

1. II and III
2. I, II and III
3. I and II
4. I and III

Which of the following compounds will undergo racemisation when solution of KOH hydrolyses? [figure]

1. (i) and (ii)
2. (ii) and (iv)
3. (iv)
4. (i) and (iv)

The order of stability of the following tautomeric compounds is [figure]

1. II > I > III
2. II > III > I
3. I > II > III
4. III > II > I

Given: [figure] I and II are

1. identical
2. a pair of conformers
3. a pair of geometrical isomers
4. a pair of optical isomers

Number of isomeric alcohols of molecular formula C6H14O which give positive iodoform test is

1. three
2. four
3. five
4. two

Which of the following acids does not exhibit optical isomerism?

1. Maleic acid
2. -amino acids
3. Lactic acid
4. Tartaric acid

The IUPAC name of the following compound is [figure]

1. trans-2-chloro-3-iodo-2-pentene
2. cis-3-iodo-4-chloro-3-pentene
3. trans-3-iodo-4-chloro-3-pentene
4. cis-2-chloro-3-iodo-2-pentene

Which of the following conformers for ethylene glycol is most stable?

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

In the following the most stable conformation of n-butane is

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

Which of the following compounds will exhibit cis-trans (geometrical) isomerism?

1. Butanol
2. 2-Butyne
3. 2-Butanol
4. 2-Butene

How many stereoisomers does this molecule have? CH3CH=CHCH2CHBrCH3

1. 8
2. 2
3. 4
4. 6

CH3-CHCl-CH2-CH3 has a chiral centre. Which one of the following represents its R-configuration?

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

If there is no rotation of plane polarised light by a compound in a specific solvent, though thought to be chiral, it may mean that

1. the compound is certainly meso
2. there is no compound in the solvent
3. the compound may be a racemic mixture
4. the compound is certainly achiral.

Which of the following is not chiral?

1. 2-Hydroxypropanoic acid
2. 2-Butanol
3. 2,3-Dibromopentane
4. 3-Bromopentane

The chirality of the compound [figure]

1. R
2. S
3. E
4. Z