Reactant : Alcohol

Reagent : Luca's Reagent (Anhydrous ZnCl2 + Conc. HCl)

Product : Alkyl chloride

Alcohols on reaction with Luca's reagent produces alkyl chlorides via unimolecular nucleophilic substitution reactions (SN1). The SN1 reaction goes through the formation of carbocation intermediate followed by the attack of nucleophile. The product received will be a mixture of both retention and inversion in configuration. It will be a partial racemic mixture. This happens due to the planarity of carbocation intermediate and the possibility of attack of nucleophile from the front side and back side. The rate of the reaction depends on the stability of carbocation. Therefore different alcohols (primary, secondary and tertiary) reacts with different rate. This characteristics of this reaction can be used as a method for the identification of different type of alcohols, known as Luca's test.