Aldehydes and Ketones

Question 1

Which oxidising agent is used to oxidise alcohols to either aldehydes or ketones, and what would
you see during the reaction?

Answer 1

acidified potassium dichromate. With when aldehydes or ketones are formed, the solution turns from orange to green

Question 2

why can ketones not be oxidised

Answer 2

because there is no hydrogen group attached to the carbonyl group (the C=O group)

Question 3

give to examples of reagents that can be used to identify aldehydes and ketones from each other

Answer 3

1) Tollens reagent, [Ag(NH3)2]+
- Ag+ ions are reduced to Ag atoms
2) Fehlings solution, contains Cu2+ ions
- Cu2+ ions are rduced to Cu atoms

Question 4

name a reagent used to reduce aldehydes and ketones

Answer 4

NaBH4 with methanol and water

Question 5

what is the organic product when CN- ions react with an aldehyde

Answer 5

you get a hydroxynitrile. the reaction is nucleophilic addition

Question 6

why is it not safe to carry out this reaction in the lab

Answer 6

HCN is highly toxic. The HCN is not stored, but made in situ by mixing KCN and dilute acid