Isomerism

Question 1

🔴️How enantiomers mixtures are distinguish

Answer 1

• Shine plane polarised light
• would rotate plane of light in opposite directions
• by the same amount

Question 2

🔴️Stereoisomerism

Answer 2

Same molecular formula and structure but different atomic arrangement in space

Question 3

🔴️Define Racemic mixture and explain why it’s formed

Answer 3

• Optically inactive
• Equal mole enantiomers in mixture
• equal probability** of planar carbonyl group C=O being attacked from above or below the **plane

Question 4

Why isn’t the pentan-2-ol produced optically active

Answer 4

racemic mixture formed (so equal amount)

Question 5

Suggest one advantage and one disadvantage of using a racemate rather than a single enantiomer in medicines.

Answer 5

adv:

• cheaper medicine due to cost of separation

disadv:

• one enantiomer may be ineffective so double dose required
• may be side effects from one enantiomer in the mixture

Question 6

Why does a molecule show optical isomerism

Answer 6

• contains asymmetric carbon
• with 4 different groups attached

Question 7

Name the type of isomerism shown by CH₃CH=CHCH3 and state the requirements for this

Answer 7

• Geometrical isomerism
• Double bond C=C
• 2 Different atoms/groups on each C