1) BaCl2+Na2SO4=BaSO4 +2NaCl
Ba2+ 2Cl-+ 2Na+ SO4 2-=BaSO4 +2Na+ 2Cl-
Ba2+ SO4 2-=BaSO4
2) NH4Cl+NaOH=NH3+H2O+NaCl
NH4+ + Cl- + Na+ OH- =NH3+H2O+Na+ Cl-
NH4+ OH- =NH3+H2O
3) CaCl2+Na2CO3= CaCO3+2NaCl
Ca2+ 2Cl- +2Na+ CO32- = CaCO3+2Cl- +2Na+
Ca2+CO32- = CaCO3
