Q. The $pK_{a}$of acetylsalicylic 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
A) Unionised in the small intestine and in the stomach
B) Completely ionised in the small intestine and in the stomach
C) Ionised in the stomach and almost unionised in the small intestine
D) Ionised in the small intestine and almost unionised in the stomach
Explanation
(d)
Aspirin is a weak acid. Due to common ion effect, it is unionised in acid medium but completely ionised in alkaline medium
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.