optical isomers

Question 1

what is a chiral molecule?

Answer 1

has 4 different groups attached to a central atom

Question 2

what is optical isomerism

Answer 2

type of stereoisomerism where molecules have the same molecule formula but different arrangments in space

Question 3

what does the presence of a chiral centre lead to

Answer 3

two possible isomers that are mirror images of each other

Question 4

what are two different isomers called

Answer 4

enantiomers

Question 5

features of enantiomers

Answer 5

• they are unique due to their effect on plane-polarised light
• each enantiomer causes the rotation of plane polarised light by 90 degrees in opposite directions

Question 6

how is a racemate formed

Answer 6

when optical isomers are produced as a pair of enantiomers in a 1:1 ratio

Question 7

what is a racemic mixture and how is it formed?

Answer 7

optical rotational effect on polarised light caused by each enantiomer causes the overall effect to be 0 as the opposite directions of rotation cancel out. the mixture is optically inactive (aka racemic mixture)

Question 8

what reaction leads to the formation of a racemic mixture

Answer 8

nucleophillic addition reaction

Question 9

nucleophilic addition

Answer 9

nucleophiles attack molecules with a carbonyl group from above or below the carbon-oxygen double bond. so two possible products of the reaction are mirror images (optical isomers)