試題詳解

40. A solution is prepared by mixing 2.0 M H3A and 2.0 M NaH2A in the equal volume (H₃A: pX_a1 = 2.10, pX_a2 = 7.20, pX_a3 = 12.30). Which one is the closest to the pH value of this mixture?
(A) 2.10
(B) 2.45
(C) 4.65
(D) 7.20
(E) 9.75