IIT/JEE Chemistry Practice #32: Protonation States and pKa

The video tutorial explores the protonation states and PKA of acetyl salicylic acid (aspirin). It explains the relationship between pH and PKA, focusing on how these factors affect the ionization of aspirin in different environments, such as the stomach and small intestine. The tutorial highlights that aspirin remains unionized in the acidic environment of the stomach and becomes ionized in the basic environment of the small intestine. This understanding is crucial for assessing the behavior of aspirin in the human body.

What is the PKA of acetyl salicylic acid, also known as aspirin?

• 3.5

• 2.0

• 5.0

• 8.0

In which part of the human body is the pH level around 2 to 3?

• Large intestine

• Stomach

• Mouth

• Small intestine

What happens to the carboxyl group of aspirin when the pH is below its PKA?

• It becomes deprotonated

• It remains protonated

• It forms a salt

• It evaporates

If the pH is significantly above the PKA of aspirin, what is the state of the carboxyl group?

• Protonated

• Neutral

• Deprotonated

• Hydrated

Where is aspirin ionized in the human body?

• In the mouth

• In the stomach

• In the small intestine

• In the bloodstream