Consider the following information about the diprotic acid ascorbic acid (H 2 As for short, molar mass = 176.1). The titration curve for disodium ascorbate, Na 2 As, with standard HCl is shown below:
-What major species is(are) present at point III?

Question

Consider the following information about the diprotic acid ascorbic acid (H 2 As for short, molar mass = 176.1).  The titration curve for disodium ascorbate, Na 2 As, with standard HCl is shown below: 
-What major species is(are) present at point III?

Quizplus · Accepted Answer

At point III, the pH is around 4.5, which is the pKa1 of ascorbic acid. At this point, ascorbic acid is in its monoprotic form, H₂As, and the major species present are HAs^- and H₂As. Therefore, the best choice is E, which includes both of these species.

Consider the Following Information About the Diprotic Acid Ascorbic Acid