1) HCN + KOH = KCN + H₂O;
H⁺ + CN⁻ + K⁺ + OH⁻ = K⁺ + CN⁻ + H₂O;
H⁺ + OH⁻ = H₂O.
2) HCN + NH₄OH = NH₄CN + H₂O;
H⁺ + CN⁻ + NH₄⁺ + OH⁻ = NH₄⁺ + CN⁻ + H₂O;
H⁺ + OH⁻ = H₂O.
3) MgSO₄ + Be(OH)₂ = Mg(OH)₂↓ + BeSO₄;
Mg⁺² + SO₄²⁻ + Be⁺² + 2OH⁻ = Mg(OH)₂↓ + Be⁺² + SO₄²⁻;
Mg⁺² + 2OH⁻ = Mg(OH)₂↓.