a)2NaOH+H₂S→Na₂S+2H₂O
2Na⁺+2OH⁻+2H⁺+S²⁻→2Na⁺+S²⁻+2H₂O
2OH⁻+2H⁺→2H₂O
NaOH+HNO₃→NaNO₃+H₂O
Na⁺+OH⁻+H⁺+NO₃⁻→Na⁺+NO₃⁻+H₂O
OH⁻+H⁺→H₂O
3NaOH+H₃PO₄→Na₃PO₄+3H₂O
3Na⁺+3OH⁻+3H⁺+PO₄³⁻→3Na⁺+PO₄³⁻3H₂O
3OH⁻+3H⁺→3H₂O
b)Ca(OH)₂+2HCl→CaCl₂+2H₂O
Ca²⁺+2OH⁻+2H⁺+2Cl⁻→Ca²⁺+2Cl⁻+2H₂O
2OH⁻+2H⁺→2H₂O
Ca(OH)₂+H₂SO₄→CaSO₄+2H₂O
Ca²⁺+2OH⁻+2H⁺+SO₄²⁻→Ca²⁺+SO₄²⁻+2H₂O
2OH⁻+2H⁺→2H₂O
Ca(OH)₂+2HNO₃→Ca(NO₃)₂+2H₂O
Ca²⁺+2OH⁻+2H⁺+2NO₃⁻→Ca²⁺+2NO₃⁻+2H₂O
2OH⁻+2H⁺→2H₂O
