Alcohols are organic compounds containing a hydroxyl (-OH) group bonded to a saturated carbon atom. They are classified as primary, secondary, or tertiary based on the number of carbons directly attached to the carbon bearing the hydroxyl group. Alcohols can be synthesized from various methods, including acid-catalyzed hydration of alkenes, hydroboration-oxidation, and reduction of carbonyl compounds. Important chemical properties include their ability to act as nucleophiles, their reactions with HX (to form alkyl halides), and their oxidation to aldehydes and ketones.