Ibuprofen is a weak acid with a p K a of 4.9 (shown with the ionizable hydrogen with a star). It is absorbed through the stomach and the small intestine as a function of polarity—charged and very polar molecules are absorbed slowly; neutral hydrophobic molecules absorb quickly. If the stomach pH is about 1.5 and the small intestine pH is about 6, where (and why) will more ibuprofen be absorbed into the bloodstream?
A.
More ibuprofen will be absorbed in the small intestine because it will be uncharged due to the pH being greater than the p K a
B.
More ibuprofen will be absorbed in the stomach because it will be uncharged due to the pH being lower than the p K a .
C.
More ibuprofen will be absorbed in the small intestine because it will be charged due to the pH being greater than the p K a .
D.
More ibuprofen will be absorbed in the stomach because it will be charged due to the pH being lower than the p K a .
E.
Ibuprofen will be absorbed equally well in both the stomach and small intestine.