Classification of Aldehydes, Ketones and Carboxylic Acids

Aldehydes, ketones and carboxylic acids are classified according to the nature of the carbon skeleton bonded to their carbonyl (or carboxyl) group. Both aldehydes and ketones contain a carbon-oxygen double bond as their functional group and are therefore together called carbonyl compounds. In aldehydes, the carbonyl carbon is bonded to at least one hydrogen atom besides an alkyl or aryl group; the resulting functional group, -CHO, is called the formyl group or the aldehydic carbonyl group. In ketones, by contrast, the carbonyl carbon is bonded to TWO alkyl or aryl groups, which may be identical (R=R') or different (R not-equal R'); this is called the ketonic carbonyl group. Carboxylic acids carry a different functional group again, -COOH, called the carboxyl group -- an -OH group bonded to the same >C=O carbon -- and this extra -OH is exactly what makes carboxylic acids chemical …