Summary Notes 3.3.8 - Aldehydes and ketones (A-level only)

Taylor’s Notes Aldehydes and Ketones

Nomenclature
IUPAC Name Skeletal Formula Structural Formula
Pentan-2-one

Propanal

Butan-2-one

Methyl Propanal

3,3-dimethylbutanone

Propenal


The Carbonyl Group is Polar because Oxygen is much more Electronegative than Carbon




Physical Properties of Carbonyls
Compound Structural Formula Formula Mass Boiling Point/°C
Propane CH3CH2CH3 44 -42
Ethanal CH3CHO 44 20
Ethanol CH3CH2OH 46 78

Carbonyls Boiling Point compared to a Corresponding Alcohol
Alcohols can hydrogen bond with one another whereas carbonyls can do pd-pd as their strongest IMF, but
Hydrogen Bonding is stronger than permanent dipole-permanent dipole attractions

Carbonyls Boiling Point compared to an Alkene of Similar Formula Mass
Alkanes can only exhibit dispersion forces as they are non-polar whereas Carbonyl’s exhibit pd-pd which is
a stronger IMF than dispersion forces

Carbonyls Hydrogen Bonding with Water Molecules (Solubility)
Carbonyl compounds are able to form hydrogen bonds with water molecules

Thus, Carbonyl compounds, especially with short chains are very soluble in water

Carbonyl Hydrogen Bonding with Water