The proper sequence of steps involved in the mono bromination of aniline is

-NH₂ group is a highly activation group toward ESR. Even n presence less polar solvents (or) even in presence of non-polar solvent, aniline gives poly substituted products. To control the reactivity of aniline it is converted to acetanilide.

-NH-CO-CH₃ group is moderately activating group. Tis is because the lone pair of electrons of nitrogen atom are not only localized on benzene ring but also on -COR group.

Thus acetanilide on bromination in presence of ethanoic acid gives p-bromo acetamide as major product, Which on hydrolysis gives p-bromo aniline in good yields.