Preparation of Aldehydes and Ketones
( i ) By oxidation of alcohols Aldehydes and ketones are generally prepared by oxidation of primary and secondary alcohols , respectively .
( ii ) By dehydrogenation of alcohols In this method , alcohol vapours are passed over heavy metal catalysts ( Ag or Cu ). Primary and secondary alcohols give aldehydes and ketones .
( iii ) By ozonolysis of alkenes
( iv ) By hydration of alkynes Acetylene on hydration gives acetaldehyde and other alkynes on hydration give ketones .