Questionnaire : Comprehending chemical structures

Which of the following shows optical activity ?

• CH₃CHBrCH₃

• CH₂BrCHBrCH₃

• CH₂BrCH₂CH₂Br

• CH₂BrCHBrCH₂Br

Which of the following does NOT exhibit geometrical isomerism ?

• 4-octene

• 2-pentene

• 3-hexene

• 2-hexene

• 1-hexene

Stereocentre is a -

(P) Carbon attached to similar groups

(Q) Carbon attached to four different groups

(R) Carbon where interchange of groups give isomers

(S) Carbon having restricted rotation

• P, S

• Q, S

• P, R

• Q, R

Enantiomers will have -

(P) Same physical properties

(Q) Same chemical properties

(R) Different physical properties

(S) Different chemical properties

• P, R

• Q, S

• R, S

• P, Q

All of the following are true regarding enantiomers EXCEPT

• Mirror images

• Non-superimposable

• Form racemic mixture

• One maybe optically inactive

How many optical isomers are possible for the given structure?

• 2

• 4

• 3

• 8

Which of the following structure permits cis-trans isomerism?

• X₂C=CY₂

• XYC=CZ₂

• X₂C=CXY

• XYC=CXY

Which of the following best describes conformational isomers?

• Molecules with different functional groups.

• Molecules with same molecular formula but different arrangements of atoms in space.

• Molecules with the same molecular formula but different number of atoms.

• Molecules with the same molecular formula and the same arrangement of atoms in space.

Which of the following statements concerning conformations is/are TRUE?

1. 1. Ethane has an infinite number of conformations.

2. 2. The eclipsed conformation of a molecule is slightly more stable and energetically favored than the staggered conformation.

3. 3. A conformation is one specific geometry of a molecule.

• 1 only

• 2 only

• 1 and 2

• 2 and 3

• 1 and 3

Identify the type of isomers (I) and (II) in the given image.

• cis-trans

• Enantiomers

• Conformers

• Diastereomers