問題詳情

22. For phosphoric acid, Ka,1 = 7.6 × 10⁻³, Ka,2 = 6.2 × 10⁻⁸, Ka,3 = 4.8 × 10⁻¹³. In order of decreasing concentrations, which of the following is correct about the concentration of the listed species present in a solution of H3PO4 at pH = 8? 
I. [PO4³⁻] II. [HPO4²⁻] III. [H2PO4⁻] IV. [H3PO4] 


(A) I ＞ II ＞ III ＞ IV
(B) I ＞ III ＞ IV ＞ II
(C) III ＞ II ＞ IV ＞ I
(D) IV ＞ I ＞ III ＞ II
(E) IV ＞ III ＞ II ＞ I