盐的水解方程式要不要打沉淀符号

不用,毕竟是促进水的电离,是中和反应的逆反应,反应程度很小.

Al2(SO4):Al3+ +3H2O <==>Al(OH)3 +3H+
Cu(NO3)2:Cu2+ +2H2O <==>Cu(OH)2 +2H+
NaHS:HS- +H2O <==>H2S +OH-
K2CO3:CO32- +H2O <==>HCO3- +OH-
Na2HPO4:HPO42- +H2O <==>H3PO4 +OH-
KF:F- +H2O <==> HF +OH-
NaClO:ClO- +H2O <=>HClO +OH-
FeSO4:Fe2+ +2H2O <==>Fe(OH)2+ 2H+
K3PO4:PO43- +H2O <==>HPO42- +OH-

不用，水解反应是可逆的