Question

Identify ortho and para directing groups from the following: \[ -\text{CHO}, -\text{NHCOCH}_3, -\text{OCH}_3, -\text{SO}_3\text{H}. \]

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

Hint:

Electron-donating groups (e.g., \( -\text{NHCOCH}_3 \), \( -\text{OCH}_3 \)) activate the ortho and para positions for substitution, while electron-withdrawing groups (e.g., \( -\text{CHO} \), \( -\text{SO}_3\text{H} \)) deactivate these positions and prefer the meta position.

Answer 1

The Correct Option is B

Electron-donating groups like \( -\text{NHCOCH}_3 \) and \( -\text{OCH}_3 \) increase electron density at the ortho and para positions of the benzene ring via resonance or inductive effects, thus directing substitution to these sites.
Conversely, electron-withdrawing groups such as \( -\text{CHO} \) and \( -\text{SO}_3\text{H} \) decrease electron density at the ortho and para positions, directing substitution to the meta position. Final Answer:\[\boxed{\text{II, III}}\]