Chapter 14, Problem 113CP

When a diprotic acid, H₂A, is titrated with NaOH, the protons on the diprotic acid are generally removed one at a time, resulting in a pH curve that has the following generic shape:

a. Notice that the plot has essentially two titration curves. If the first equivalence point occurs at 100.0 mL NaOH added, what volume of NaOH added corresponds to the second equivalence point?

b. For the following volumes of NaOH added, list the major species present after the OH⁻ reacts completely.

i. 0 mL NaOH added

ii. between 0 and 100.0 mL NaOH added

iii. 100.0 mL NaOH added

iv. between 100.0 and 200.0 mL NaOH added

v. 200.0 mL NaOH added

vi. after 200.0 mL NaOH added

c. If the pH at 50.0 mL NaOH added is 4.0, and the pH at 150.0 mL NaOH added is 8.0, determine the values $K_{{\text{a}}_{\text{1}}}$_, and $K_{{\text{a}}_2}$ for the diprotic acid.