The reaction between salicylic acid (C7H6O3) and acetyl chloride (CH3COCl) is an example of an acylation reaction, where an acyl group (-C(O)CH3) from the acetyl chloride is transferred to the salicylic acid. The reaction can be represented by the following equation:

C7H6O3 (salicylic acid) + CH3COCl (acetyl chloride) → C9H8O4 (acetylsalicylic acid) + HCl (hydrochloric acid)

In this reaction, the hydroxyl group (-OH) of the salicylic acid reacts with the acetyl chloride to form an ester bond (-COO-), resulting in the formation of acetylsalicylic acid (also known as aspirin), along with the release of hydrochloric acid as a byproduct.