Physical Properties of Aldehydes and Ketones
1 . Methanal ( HCHO ) is a gas at room temperature . and its 40 % aqueous solution is known as formalin . It is a reducing agent in silvering of mirrors and decolourising vat dyes .
2 . Ethanal ( CH3CHO ) is a volatile liquid . Other aldehydes and ketones are liquid or solid at room temperature .
3 . The boiling point of aldehydes and ketones are higher than hydrocarbons and ethers of comparable molecular mass due to high magnitude of dipole-dipole interactions .
4 . Aldehydes and ketones have lower boiling point than those of alcohols of similar molecular
masses due to absence of intermolecular hydrogen bonding .
5 . The lower members of aldehydes and ketones are miscible with water due to the formation of hydrogen bond with water . However , the solubility decreases with increase in length of alkyl chain .
6 . Acetophenone is a hypnotic ( sleep producing drug ) so used as a medicine under the name hypnone .
Chemical Reactions of Aldehydes and Ketones