Oxidation of different alcohols in the presence of suitable oxidizing agents gives aldehydes and ketones. Partially oxidizing a primary alcohol using a mild oxidizing agent produces an aldehyde. If, instead, a strong oxidizing agent is used, the aldehyde gets further oxidized to a carboxylic acid. Irrespective of the strength of the oxidizing agent, oxidation of a secondary alcohol produces a ketone. Aldehydes and ketones are also prepared from unsaturated hydrocarbons like alkenes and alkynes. Gently cleaving a monosubstituted alkene using ozone, followed by a reductive workup, yields formaldehyde, and a substituted aldehyde. Similarly, cleaving a 1,2-disubstituted alkene gives a mixture of aldehydes, while a 1,1-disubstituted alkene gives a mixture of formaldehyde and ketone. Ozonolysis of a trisubstituted alkene produces a mixture of aldehydes and ketones, while a tetrasubstituted alkene gives only ketones. Terminal alkynes on hydroboration-oxidation through anti-Markovnikov addition give aldehydes, while internal alkynes give ketones. However, both terminal and internal alkynes favor Markonikov’s addition under acid-catalyzed hydration conditions to give ketones.