The structure of the compound that gives a tribromo derivative on treatment with bromine water is:

Bromine water reacts with phenols to substitute all available ortho and para positions.m-cresol (3-methylphenol): The $-\text{OH}$ group is at 1 and $-{\text{CH}}_3$ at 3. The available ortho positions to $-\text{OH}$ are 2, 4, and 6. All three are open. Thus, it gives a tribromo derivative.o-cresol: Only two positions (4, 6) are available.p-cresol: Only two positions (2, 6) are available.