## Chemistry and Chemical Reactivity (9th Edition)

$\ \ \ \ HPO_4^{2-}+H_2O\leftrightarrow PO_4^{3-}+H_3O^+\ -->K_{a3}$ $+ \ PO_4^{3-}+H_2O\leftrightarrow HPO_4^{2-}+OH^-\ --> K_{b1}$ --- $\ \ \ \ 2\ H_2O\leftrightarrow H_3O^++OH^-\ --> K_w$