Ответ:

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