The `pK_(a)` of acteylsalicylic acid (aspirin) is `3.5`. The pH of gastric juice in human stomach is about `2-3` and the pH in the small intestine is about 8. Aspirin will be:

Options

A. unionised in the small intestine and in the stomach
B. completely ionized in the small intestine and in the stomach
C. ionized in the stomach and almost unionised in the small intestine
D. ionized in the small intestine and almost unionised in the stomach

Answer

D

Explanation

In stomach, pH is 2-3, i.e. strongly acidic and aspirin will be almost unionised here due to common ion effect. However,pH in small intestine is 8, basic, aspirin will be neutralized here.