Question 1

What is an asymmetric carbon?

Accepted Answer

An asymmetric carbon is bonded to four different groups. In this model, the central carbon is attached to OH, CHO, CH2OH and hydrogen, so it has a distinct 3D configuration.

Question 2

What is chirality in a molecule?

Accepted Answer

Chirality is the property by which a molecule is not superimposable on its mirror image. A chiral molecule and its mirror image are called enantiomers.

Question 3

What happens when two groups on an asymmetric carbon are interchanged?

Accepted Answer

If that carbon is the molecule's only stereogenic centre, one interchange of any two groups produces its enantiomer, and exchanging the same pair again restores the original configuration. If other stereogenic centres are present, inversion at only one centre generally produces a diastereomer.

Question 4

What is the difference between stereoisomers and structural isomers?

Accepted Answer

Stereoisomers have the same connectivity between atoms but differ in their spatial arrangement. Structural isomers have different connectivity, so their atoms are joined in a different order.

Question 5

Why is a racemic mixture optically inactive?

Accepted Answer

A racemic mixture contains equal amounts of two enantiomers. Their equal and opposite rotations of plane-polarised light cancel because of external compensation, giving zero net optical rotation.

Chirality and Enantiomers 3D Lab

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