Ba(OH)2 + SO3 -> BaO + NaOH -> Ba(OH)2 + H2CO3 -> ZnSO4 + NaOH -> Zn(OH)2 -> Mg(OH)2 + HNO3 ->
1. Ba(OH)2 + SO3 -> BaSO4 + H2O
2. BaO + NaOH -> BaOH+NaO
3. Ba(OH)2 + H2CO3 -> BaCO3 + 2H2O
4. ZnSO4 + NaOH -> Na(SO4)2+Zn(OH)2
5. Zn(OH)2 -> ZnO + H2O
6. Mg(OH)2 + HNO3 -> MgNO3+2H2O