后酒子太学 Shihezi University 口多元酸（碱）在水中逐级离解，情况比较复杂。例如HPO: H3P04+H20=H2P0+H304=7.52×10-3 H2P0+H20=HP0,2+H30Ka=6.23×108 HPO +H,O=PO+H.O K43=22×10-13 由值可知，酸的强度HPO4>H,P04>HP02。� 多元酸（碱）在水中逐级离解，情况比较复杂。例如 多元酸（碱）在水中逐级离解，情况比较复杂。例如H33PO44: − + H3PO4 + H2O = H2PO4 + H3O 3 1 7.52 10 − Ka = × − − + H PO + H O = HPO + H3O 2 2 4 2 4 8 2 6.23 10 − Ka = × − − + HPO + H O = PO + H3O 3 4 2 4 13 3 2.2 10 − Ka = × 由Kaa值可知，酸的强度 值可知，酸的强度H33PO44>>H22PO44 ->>HPO44 2-2-