An aldehyde CH3CH2CH2CHO reacts with potassium cyanide (KCN) to form a racemic mixture of two stereoisomers of CH3CH2CH2CH(OH)CN. A)Explain why a racemic mixture is formed and b)describe how you would distinguish between 2 samples of the stereoisomers

A) The aldehyde contains a planar carbon group which can be attacked from both sides. Each side has equal probability of being attacked resulting in a racemic compound containing equal amounts of each stereoisomer.B) Shine plane polarised light on the compounds, each will rotate light in opposite directions.