In the Titration of 250

Multiple Choice

In the titration of 250.0 mL of 0.20 M H₃PO₄ with 0.10 M NaOH, the pH of the solution after the addition of some NaOH is 4.66. Which of the following phosphate-containing species is present in the largest amount? For H₃PO₄, K_a1 = 7.5  10^-3, K_a2 = 6.2  10^-8, and K_a3 = 4.8  10^-13.

A) H₂PO₄^-
B) H₃PO₄
C) PO₄^3-
D) HPO₄^2-