The pKa of acetylsalicylic acid (aspirin) is 3.5. The pH of gastric juice in human stomach is about — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The extent of ionization is determined by the pH relative to the $pK_a$. In the stomach (pH 2-3), the pH is less than the $pK_a$ (3.5), so the acid is predominantly in its protonated, unionized form. In the small intestine (pH 8), the pH is much greater than the $pK_a$, so the acid is predominantly in its deprotonated, ionized form.