1，低价态的还原性：

4Fe(OH)2+O2+2H2O===4Fe(OH)3

2NaOH+SO2(少量)===Na2SO3+H2O

NaOH+SO2(足量)===NaHSO3

1，与酸性物质的作用：

2NaOH+SiO2===NaSiO3+H2O

2NaOH+Al2O3===2NaAlO2+H2O

2NaOH+Cl2===NaCl+NaClO+H2O

NaOH+HCl===NaCl+H2O

NaOH+H2S(足量)===NaHS+H2O

2NaOH+H2S(少量)===Na2S+2H2O

3NaOH+AlCl3===Al(OH)3+3NaCl

NaOH+Al(OH)3===NaAlO2+2H2O

(AlCl3和Al(OH)3哪个酸性强?)

NaOH+NH4Cl===NaCl+NH3+H2O

Mg(OH)2+2NH4Cl===MgCl2+2NH3.H2O

Al(OH)3+NH4Cl不溶解

3,不稳定性:Mg(OH)2===MgO+H2O

2Al(OH)3===Al2O3+3H2O

2Fe(OH)3===Fe2O3+3H2O

Cu(OH)2===CuO+H2O