Lucas test: A lcohols react w ith concentrated hydrochloric acid in presence of anhydrous zinc chloride to form alkyl halides R−OH+HCIZnclX2Alkyl halideR−Cl+H2O
The three types of alcohols undergo this reaction at different rates. The rates of reaction with Lucas reagent, [conc. HCl+ZnCl2 (anhydrous)) follow the order : 3∘>2∘>1∘