aldehydes and ketones

Question 1

by considering the mechanism of the reaction explain why the product has no effect on plane polarised light

Answer 1

Stage 1: Formation of product
• Nucleophilic attack
• Planar carbonyl group
• H – attacks from either side (stated or drawn)

Stage 2: Nature of
product
• Product of step 1 shown
• This exists in two chiral forms (stated or drawn)
• Equal amounts of each enantiomer / racemic mixture formed

Stage 3: Optical activity
• Optical isomers / enantiomers rotate the plane of polarised light equally