NCERT · Class 12 · Chemistry · Alcohols, Phenols and EthersHow can you distinguish between primary, secondary, and tertiary alcohols using Lucas reagent?

Lucas reagent, which is an anhydrous mixture of concentrated hydrochloric acid and zinc chloride, is effectively used to distinguish between the three classes of alcohols based on their differing reactivity rates toward nucleophilic substitution. Tertiary alcohols react immediately with Lucas reagent at room temperature, producing an instant turbidity or cloudiness due to the rapid formation of an insoluble alkyl chloride. Secondary alcohols form turbidity within 5 minutes, whereas primary alcohols do not show any turbidity at room temperature.