Phenol on treatment with bromine water gives:
2,4,6 Tribromo phenol
Phenol on treatment with bromine water gives polyhalogen derivatives in which all the o- and p- positions with respect to -OH group are replaced by bromine. In aqueous solution, phenol ionizes to form phenoxide ion and due to the presence of negative charge oxygen of the phenoxide ion donates electron to the benzene ring and activates it strongly.