The reaction of tert-butyl alcohol t-BuOH with hydrochloric acid HCl to form tert-butyl chloride t-BuCl is an example of an acid-catalyzed substitution reaction specifically, an SN1 reaction .The mechanism involves the following steps:1. Protonation of the alcohol: The oxygen atom in the tert-butyl alcohol molecule is protonated by the hydrochloric acid, forming a protonated tert-butyl alcohol intermediate t-BuOH2+ . This step is reversible.t-BuOH + HCl t-BuOH2+ + Cl-2. Formation of the carbocation: The protonated tert-butyl alcohol intermediate undergoes heterolysis, breaking the O-H bond and releasing a water molecule. This results in the formation of a tert-butyl carbocation intermediate t-Bu+ , which is a highly reactive species.t-BuOH2+ t-Bu+ + H2O3. Nucleophilic attack: The chloride ion Cl- acts as a nucleophile and attacks the carbocation, forming the tert-butyl chloride product.t-Bu+ + Cl- t-BuClIn summary, the intermediates involved in this reaction are the protonated tert-butyl alcohol t-BuOH2+ and the tert-butyl carbocation t-Bu+ . The mechanism is an SN1 reaction, which involves the formation of a carbocation intermediate and a nucleophilic attack by the chloride ion.