In aldehydes, the carbonyl group has a hydrogen atom attached to it together with either:

• a second hydrogen atom or, more commonly, a hydrocarbon group which might be an alkyl group or one containing a benzene ring

• a third hydrogen atom with another R group

• one hydrogen atom with two R groups

How do you make aldehydes?

• by oxidising primary alcohols

• by a reflux experiment

• By heating up a ketone

Which is an aldehyde?

Are aldehydes soluble?

• Yes

• No

• Only short chain aldehydes

Which statement is true?

• An aldehyde differs from a ketone by having a hydrogen atom attached to the carbonyl group. This makes the aldehydes very easy to oxidise.

• An aldehyde and a ketone are very similar and act in the same way when you try to oxidise them

• Ketones have that hydrogen atom and are not resistant to oxidation.

Aldehydes are...

• usually more reactive toward nucleophilic substitutions than ketones because of both steric and electronic effects.

• atomically extremely heavy

• do not oxidise