Q.Identify A, B and C: salicylic acid (2-hydroxybenzoic acid, a ring bearing both -OH and -COOH) --SOCl2--> A --NH3--> B --LiAlH4--> (C)

Step 1. Salicylic acid (2-hydroxybenzoic acid) has two functional groups, a ring -COOH and a ring -OH. SOCl2 reacts specifically and cleanly with the CARBOXYLIC ACID (converting -COOH to the far more reactive acid chloride, -COCl, + SO2 + HCl, both gases that simply escape); the phenolic -OH, attached directly to the aromatic ring, does not react with SOCl2 under these conditions, so A = 2-hydroxybenzoyl chloride, with the phenolic -OH intact.

Step 2. A + NH3 is a nucleophilic acyl substitution: ammonia's nitrogen attacks the acid chloride's carbonyl carbon, displacing chloride and forming the amide, B = salicylamide (2-hydroxybenzamide), again with the phenolic -OH untouched throughout. …

Track which of salicylic acid's TWO functional groups each reagent actually reacts with -- SOCl2 and the LiAlH4 reduction that follows both act only on the carboxylic-acid-derived chain, leavi …

• Assuming SOCl2 or LiAlH4 also converts the phenolic -OH into a chloride or removes it -- SOCl2 is selective for a carboxylic acid (or an aliphatic alcohol) over an aromatic phenolic -OH under these conditions, and LiAlH4 reduce …