Consider the following information about the diprotic acid ascorbic acid (H₂As for short, molar mass = 176.1) . The titration curve for disodium ascorbate, Na₂As, 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 (H₂As for short, molar mass = 176.1) .

Consider the following information about the diprotic acid ascorbic acid (H<sub>2</sub>As for short, molar mass = 176.1) . The titration curve for disodium ascorbate, Na<sub>2</sub>As, with standard HCl is shown below: -What major species is(are) present at point III? A) HAs<sup>-</sup> only B) H<sub>2</sub>As and H<sup>+</sup> C) H<sub>2</sub>As only D) As<sup>2-</sup> and HAs<sup>-</sup> E) HAs<sup>-</sup> and H<sub>2</sub>As

The titration curve for disodium ascorbate, Na₂As, with standard HCl is shown below:

-What major species is(are) present at point III?

Quizplus · Accepted Answer

At point III of the titration curve, the pH is around 4. At this pH, ascorbic acid exists primarily in the form of the HAs^- species (i.e. deprotonated once). However, there is also some H₂As (i.e. undeprotonated) present. Therefore, the major species present at point III are HAs^- and H₂As.

Consider the Following Information About the Diprotic Acid Ascorbic Acid