Which statements about acetanilide are true?

Which statements about acetanilide are true?

• A. I and II
• B. III and IV
• C. I and III
• D. II and IV

Answer: (B)

Acetanilide behaves differently from aniline because the amide is attached to the nitrogen. The lone pair on nitrogen participates in resonance with the carbonyl of the acetyl group, so it is less available to accept a proton. That resonance involvement makes acetanilide significantly less basic than aniline. Because the ring’s electron density is moderated by this acylation, the ring is not as highly activated as with aniline, but the substituent still directs electrophilic attack mainly to the para position (with some ortho present). This para-directing tendency arises from resonance forms that place positive charge at the para site, and steric factors often favor para over ortho in the substituted system. So the statements that correctly capture acetanilide’s properties are those describing its reduced basicity and its para-directing behavior. The option that pairs these two true points is the right choice.

Acetanilide behaves differently from aniline because the amide is attached to the nitrogen. The lone pair on nitrogen participates in resonance with the carbonyl of the acetyl group, so it is less available to accept a proton. That resonance involvement makes acetanilide significantly less basic than aniline.

Because the ring’s electron density is moderated by this acylation, the ring is not as highly activated as with aniline, but the substituent still directs electrophilic attack mainly to the para position (with some ortho present). This para-directing tendency arises from resonance forms that place positive charge at the para site, and steric factors often favor para over ortho in the substituted system.

So the statements that correctly capture acetanilide’s properties are those describing its reduced basicity and its para-directing behavior. The option that pairs these two true points is the right choice.