What is a common method for preparing aldehydes and ketones, and how are they obtained through this method?

A common method for preparing aldehydes and ketones is oxidation of primary and secondary alcohols, respectively. Oxidation of primary alcohols, typically using mild oxidizing agents like PCC (pyridinium chlorochromate), results in the formation of aldehydes. Secondary alcohols are oxidized using stronger oxidizing agents like potassium dichromate (K₂Cr₂O₇) or sodium dichromate (Na₂Cr₂O₇) to yield ketones. During these processes, the alcohol’s hydroxyl group is oxidized to a carbonyl group, leading to the formation of the corresponding aldehyde or ketone, depending on the starting alcohol’s substitution pattern.