Blood is a buffered solution with pH values ranging from 7.35-7.45. The importan
ID: 897249 • Letter: B
Question
Blood is a buffered solution with pH values ranging from 7.35-7.45. The important components of blood that contribute to its buffering capacity are species derived from carbonic acid and phosphoric acid. This problem emphasizes the phosphoric acid component.
(a) Identify the three additional species in solution that can be derived from phosphoric acid using Brønsted-Lowry acid-base concepts.
(b) Write the three equilibria that relate phosphoric acid with each of these species listed in part (a).
Explanation / Answer
A) H3PO4 -------> H+ + H2PO4-
Ka = {[H2PO4-]*[H+]}/[H3PO4]
H2PO4- ------> H+ + HPO42-
Ka = {[HPO42-]*[H+]}/[H2PO4-]
HPO42- ---------> PO43- + H+
Ka = {[PO43-]*[H+]}/[HPO42-]