Everything from the 2 lessons of this topic on a few pages: the key idea of each lesson, the diagram to remember, the points to learn and the traps examiners set. Read it, cover it, test yourself.
Alcohols contain the –OH group. Hydrogen bonding between molecules gives them much higher boiling points than alkanes of similar Mr, and lets short-chain alcohols mix with water. They are made by hydrating alkenes, hydrolysing halogenoalkanes, reducing carbonyl compounds or hydrolysing esters. They react with sodium to give an alkoxide and hydrogen (more slowly than water, as alcohols are weaker acids); with HX, PCl5 or SOCl2 to give halogenoalkanes; with hot concentrated acid or Al2O3 by dehydration to alkenes; and with carboxylic acids, using a concentrated H2SO4 catalyst, to form esters.
Alcohols react with sodium more slowly than water does, because they are weaker acids: the ethyl group pushes electron density towards O, making O–H harder to break. In esterification, the concentrated H2SO4 is a catalyst and the reaction is reversible, so yields are well below 100%.
Acidified potassium dichromate(VI) is a mild oxidising agent; when it oxidises an alcohol, orange Cr2O72− is reduced to green Cr3+. A primary alcohol is oxidised to an aldehyde, which must be distilled off as it forms; with excess oxidant heated under reflux it goes on to a carboxylic acid. A secondary alcohol gives a ketone. A tertiary alcohol is not oxidised, because the C–OH carbon has no hydrogen. The tri-iodomethane test (alkaline iodine, warm) gives a pale yellow precipitate of CHI3 with alcohols containing CH3CH(OH)–.
Distillation gives the aldehyde; reflux gives the carboxylic acid. The colour change is orange to green. Tertiary alcohols are not oxidised because there is no hydrogen on the carbon bearing the OH. The tri-iodomethane test needs a CH3 group next to the CH(OH), so propan-1-ol is negative.