Would 4-bromoacetanilide or 4-bromo-2-chloroacetanilide be more reactive toward electrophilic substitution? explain.

Answer: -

4-Bromoacetanilide will be more reactive toward electrophilic substitution than 4-bromo-2-chloroacetanilide.

Explanation: -

Electrophilic substitution depends on the electron density of the aromatic ring. More the electron density, more is the reactivity.

Chloro is a electron withdrawing group. So it reduces the electron density of the aromatic benzene ring, thus decreasing the electron density.

Thus, 4-Bromoacetanilide will be more reactive toward electrophilic substitution than 4-bromo-2-chloroacetanilide.