Answer:
The acid (-COOH) functional group of aspirin causes it to irritate the stomach
Step-by-step explanation:
Aspirin is acetylsalicylic acid with a molecular formula C₉H₈O₈.
It is a cyclic compound composed of a benzene ring along with 2 functional groups: the carboxylic acid (-COOH) and acetyl group (-OCOCH3)
The most common side effect of consuming aspirin is an upset stomach. This is due to the acid functional group which can irritate the stomach lining.