Optical Isomerism

Question 1

Optical isomerism occurs when…

Answer 1

…a carbon atom bonds to four different groups

Question 2

What is optical isomerism?

Answer 2

Optical isomers rotate plane polarised light. One isomer will rotate it clockwise and the other anticlockwise.

Question 3

What is a racemic mixture

Answer 3

A mixture which contains equal quantities of enantiomers

Question 4

Why can a Nucleophilic addition to aldehydes and ketones result in a racemic mixture of optical isomers?

Answer 4

• Bonding around C=O group in aldehyde and ketone is planar
• This means there is 50:50 chance of the Nucleophilic attacking from either side
• This results in equal proportions of each optical isomer forming, and so racemic mixture is formed