Aldehydes and Ketones

• aldehydes and ketones are both carbonyl compounds as they contain the carbonyl functional group C=O
• Aldehydes are readily oxidised to carboxylic acids
• tollens reagent is a colourless solution of silver nitrate dissolves in aqueous ammonia. when its heated with an aldehyde a silver mirror forms
• fehlings solution is a blue solution made of copper (II) ions dissolved in sodium hydroxide. when it is heated with an aldehyde it forms a brick red precipitate
• Aldehydes can be reduced to primary alcohols, and ketones to secondary alcohols, using NaBH4 in aqueous solution. These reduction reactions are examples of nucleophilic addition.
• hydroxynitriles are molecules containing a hydroxyl (-OH) and a nitrile (-CN) group
• hydroxynitriles can be produced by reacting an aldehyde or ketone with potassium cyanide (KCN) followed by a dilute acid. this is an example of a nucleophilic addition reaction
• hydroxynitriles can form a racemic mixture as the carbonyl group in aldehydes and unsymmetric ketones are planar so the nucleophile (CN-) can attack from either direction
• KCN is toxic
• nucleophilic addition mechanism