The reaction that combined the salicylic acid and acetic acid to form acetylsalicylic acid is called esterification. Esterification is the process of forming esters from carboxylic acids. An ester is when a carbon is connected to two oxygens, but one of the oxygens isn't connected to anything else (so it is double-bonded to the carbon), while the other oxygen is connected to another carbon.
Ethanol reacts with ethanoic acid on warming in the presence of a few drops of concentrated sulphuric acid to form a sweet smelling ester, ethyl ethanoate
