The acid-catalyzed cleavage of an ether using HBr proceeds through the following mechanism:1. Protonation of the ether: The reaction begins with the protonation of the ether oxygen by the strong acid HBr. This step is reversible and generates a protonated ether, which is a better electrophile than the starting ether.R-O-R' + HBr R-O H -R' + Br^-2. Nucleophilic attack: The bromide ion Br^- acts as a nucleophile and attacks the more substituted carbon atom of the protonated ether. This leads to the formation of a new C-Br bond and the breaking of the C-O bond. The result is the formation of an alkyl bromide and an alcohol.R-O H -R' + Br^- R-Br + R'-OH3. Proton transfer optional : If the initially formed alcohol is a tertiary alcohol, it can undergo further reaction with HBr to form another alkyl bromide and water. This step involves the protonation of the alcohol oxygen, followed by the nucleophilic attack of Br^- on the carbon atom.R'-OH + HBr R'-O H -H + Br^-R'-O H -H + Br^- R'-Br + H2OIn summary, the acid-catalyzed cleavage of an ether using HBr involves the protonation of the ether, nucleophilic attack by the bromide ion, and optional proton transfer for tertiary alcohols. The products are alkyl bromides and alcohols or water if the tertiary alcohol undergoes further reaction .