8 Aldehydes and Ketones

Question 1

carbonyl group

Answer 1

is planar group so in nucelophilic addition, the nucelophile can be added above or below the group. It has an equal chance of being added above or below so forms a racemic mixture
is polar so the Cδ+ attracts nucelophiles

Question 2

reduction of carbonyls

Answer 2

nucelophilic addition
uses NaBH4 (aq) catalyst as it provides H- and is selective
first, H- attacks polar carbon
then, O- attacks a H from the solvent

Question 3

reduction of aldehydes

Answer 3

primary alcohols

Question 4

reduction of ketones

Answer 4

secondary alcohols

Question 5

addition of HCN

Answer 5

requires KCN and a dilute acid (e.g. HCl)
produces hydroxynitriles, which contain a chiral carbon

Question 6

why do we use KCN instead of HCN?

Answer 6

HCN is very toxic so is generated by reaction of KCN with dilute HCl (aq)