Phenol on treatment with CO₂ in the presence of NaOH followed by acidification produces compound X as the major product. X on treatment with (CH₃CO)₂O in the presence of catalytic amount of H₂SO₄ produces : 

The very first reaction in the above road map looks like Kolbe’s reaction which results to salicylic acid as : 

The salicylic acid with acetic anhydride [(CH₃CO)₂O] in the presence of catalytic amount of conc. H₂SO₄ undergoes acylation to produce aspirin as: 

Aspirin is a non-narcotic analgesic (pain killer).