Choose the correct answer from the options given below.
Answer: A → III, B → I, C → II, D → IV
Solution
Phenol heated with zinc dust undergoes reductive removal of the −OH group (deoxygenation) to give benzene.
Phenol treated with CHCl3 and NaOH, then acidified with HCl (Reimer–Tiemann reaction), introduces a −CHO group at the position ortho to −OH, giving salicylaldehyde.
Phenol treated with CO2 and NaOH under pressure, then acidified with HCl (Kolbe–Schmidt reaction), carboxylates the ortho position, giving salicylic acid.
Phenol treated with concentrated HNO3 nitrates all three activated positions to give 2,4,6-trinitrophenol, picric acid.