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