Photo AI
The aldehyde CH₃CH₂CH₂CHO reacts with KCN followed by dilute acid to form a racemic mixture of the two stereoisomers of CH₃CH₂CH(CH₃)(OH)CN - AQA - A-Level Chemistry - Question 4 - 2017 - Paper 2
Question 4
The aldehyde CH₃CH₂CH₂CHO reacts with KCN followed by dilute acid to form a racemic mixture of the two stereoisomers of CH₃CH₂CH(CH₃)(OH)CN. 0 4.1 Give the IUPAC na... show full transcript
Worked Solution & Example Answer:The aldehyde CH₃CH₂CH₂CHO reacts with KCN followed by dilute acid to form a racemic mixture of the two stereoisomers of CH₃CH₂CH(CH₃)(OH)CN - AQA - A-Level Chemistry - Question 4 - 2017 - Paper 2
Step 1
Step 2
Describe how you would distinguish between separate samples of the two stereoisomers of CH₃CH₂CH(CH₃)(OH)CN.
Answer
To distinguish between the two stereoisomers, you could use plane polarized light. The enantiomers will rotate the plane of polarized light in opposite directions, which allows you to differentiate them.
Step 3
Explain why the reaction produces a racemic mixture.
Answer
The reaction produces a racemic mixture because the intermediate formed does not lead to preferential formation of one stereoisomer over the other. The nucleophile attacks the planar carbonyl group from either side with equal probability, resulting in equal amounts of both isomers, leading to the creation of a racemic mixture.
Step 4
Draw the structure of the compound formed and justify why it does not show stereoisomerism.
Answer
The compound formed in the reaction is CH₃(CH₂)₃C(OH)(CN).
Justification: This compound does not exhibit stereoisomerism because it does not contain a chiral center. The carbon atom bonded to the hydroxyl group (OH) is attached to two identical groups (CH₃), which prevents the formation of stereoisomers.