1)MgCO3+2NaOH=Na2CO3+Mg(OH)2<span>↓</span>
<span> Mg 2+ + CO3 2- + 2Na+ + 2OH- = 2Na+ + CO3 2- + Mg(OH)2</span>
<span> Mg 2+ + 2OH- = Mg(OH)2</span>
<span>2)NaOH+Al(OH)3=Na[Al(OH)4]</span>
<span>3)2NaOH+SO2=Na2SO3+H2O</span>
<span>4)2NaOH+ZnCl2=Zn(OH)2<span>↓+2NaCl</span></span>
<span><span> 2Na+ + 2OH- + Zn 2+ + 2Cl- =Zn(OH)2 + 2Na+ + 2Cl-</span></span>
<span><span> Zn 2+ + 2OH- =Zn(OH)2</span></span>