The lone pair of electrons on nitrogen of acetanilide  interacts
with oxygen atom due to resonance as shown below:
Rationalised 2023-24
273
Amines
Hence, the lone pair of electrons on nitrogen is less available for
donation to benzene ring by  resonance Therefore, activating
effect of –NHCOCH3 group is less than that of amino group (b) Nitration: Direct nitration of aniline yields tarry oxidation
products in addition to the nitro derivatives Moreover, in the
strongly acidic medium, aniline is protonated to form the
anilinium ion which is meta directing