Mg(OH)2+2HCl--->MgCl2+2H2O
Mg2+ +2OH- +2H+ +2Cl- --->Mg2+ +2Cl- +2H2O
2OH- +2H+ --->2H2O
NaOH+HNO3--->NaNO3+H2O
Na+ +OH- +H+ +NO3- --->Na+ +NO3- +H2O
OH- +H+ --->H2O
Ca(OH)2+H2SO4--->CaSO4+2H2O
Ca2+ +2OH- +2H+ +SO4 2- --->Ca2+ +SO4 2- +2H2O
2OH- +2H+ --->2H2O