The molecule C6H5OH is phenol. The functional group present in phenol is the hydroxyl group -OH attached to a benzene ring.The reaction between phenol C6H5OH and hydrobromic acid HBr is an electrophilic aromatic substitution reaction. In this case, it is a bromination reaction where the hydroxyl group -OH in phenol is ortho/para-directing, meaning that the bromine atom will attach to either the ortho position adjacent to the -OH group or the para position opposite to the -OH group on the benzene ring. The detailed mechanism is as follows:1. Protonation of the hydroxyl group:The lone pair of electrons on the oxygen atom of the hydroxyl group in phenol interacts with the hydrogen atom of HBr, forming a bond and resulting in the protonation of the hydroxyl group. This generates a good leaving group H2O and a positively charged oxygen atom.C6H5OH + HBr -> C6H5O H2 + Br2. Formation of the resonance-stabilized carbocation:The positively charged oxygen atom pulls electrons from the oxygen-hydrogen bond, causing the water molecule to leave and generating a resonance-stabilized carbocation a positively charged carbon atom at the ortho and para positions of the benzene ring.C6H5O H2 -> C6H5 resonance-stabilized + H2O3. Nucleophilic attack by bromide ion:The negatively charged bromide ion Br acts as a nucleophile and attacks the resonance-stabilized carbocation at either the ortho or para positions, forming a new carbon-bromine bond.C6H5 resonance-stabilized + Br -> C6H4BrOH ortho- or para-bromophenol The final products of this reaction are ortho-bromophenol and para-bromophenol, along with water as a byproduct.