Aldehydes and Ketones exhibit the following type of somerism:

(a) Chain (nuclear) Isomerism. Aldehydes with 4 or m1ore carbon atoms and ketones with five or more carbon atoms show chain isomerism. For example:

(b) Position lsomerism. Aromatic aldehydes and higher ketones give position isomers. For example:

(c) Functional Isomerism. The general formula of aldehydes, ketones, unsaturated alcohols oxiranes and oxolanes is C_nH_2nO

C₃H₆O has isomers as: