Chirality Quiz

In specific rotation values, a positive rotation indicates:

• A. Dextrorotary (clockwise) rotation

• B. Levorotary (counterclockwise) rotation

• C. Absence of optical activity

• D. An unstable solution

Which optical property of enantiomers can be quantified using a polarimeter?

• A. Specific rotation.

• B. Enantiomeric excess.

• C. The absolute configuration of chiral centers.

• D. Molecular weight

What is the relationship between the components of a racemic mixture?

• A. They are diastereomers with equal quantities of each enantiomer

• B. They are constitutional isomers in a 1:1 ratio

• C. They are identical compounds in varying proportions

• D. They are a pair of enantiomers mixed in a 1:1 ratio

In an R-configured chiral center, what is the direction of rotation?

• A. Clockwise

• B. Counterclockwise

• C. Both clockwise and counterclockwise

• D. It depends on the number of chirality centers

How do enantiomers and diastereomers differ in terms of their physical properties?

• A. Enantiomers have the same boiling points and different optical activities.

• B. Diastereomers have different chemical reactivities and identical optical rotations.

• C. Enantiomers have identical physical properties except for their effect on plane-polarized light.

• D. Diastereomers have the same physical properties, including their effect on plane-polarized light.

Which of the following statements about chirality is incorrect?

• A. A chiral molecule has a non-superimposable mirror image.

• B. Chirality is always associated with the presence of a stereocenter.

• C. A molecule with two stereocenters is always chiral.

• D. Chirality can be observed in compounds other than organic molecules.

In the context of optical activity, what is one main feature that distinguishes a racemic mixture from a meso compound?

• A. A racemic mixture has no optical activity, while a meso compound rotates light.

• B. Both racemic mixtures and meso compounds are optically inactive.

• C. A meso compound is optically inactive due to internal compensation, a racemic mixture due to external compensation.

• D. Both racemic mixtures and meso compounds exhibit optical rotation, but in opposite directions.

Which property can be used to distinguish between a mixture of enantiomers and a racemic mixture?

• A. Melting point analysis.

• B. Chromatography using a chiral stationary phase.

• C. Mass spectrometry.

• D. Infrared spectroscopy.

What is the significance of enantiomeric excess (ee) in stereoisomeric mixtures?

• A. It quantifies the percentage by weight of one enantiomer over another.

• B. It measures the ratio of diastereomers in a mixture.

• C. It defines the ratio of meso forms present in the sample.

• D. It represents the excess of one enantiomer over its mirror image in a mixture.

When assigning absolute R/S configuration, which of the following factors is not considered?

• A. The atomic number of the atoms directly attached to the chiral center.

• B. The spatial orientation of substituents around the chiral center.

• C. Electronegativities of the substituent groups.

• D. The priorities of substituent groups according to Cahn-Ingold-Prelog rules.