Pb(CH3COO)2 + Na2S = 2CH3COONa + PbS
Pb²⁺ + 2CH3COO⁻ + 2Na⁺ + S²⁻ = 2CH3COO⁻ + 2Na⁺ + PbS
Pb²⁺ + S²⁻ = PbS
Ca(OH)2 + CO2 = CaCO3 + H2O
Ca²⁺ + 2OH⁻ + CO2 = CaCO3 + H2O
Al2O3 + 6HCl = 2AlCl3 + 3H2O
Al2O3 + 6H⁺ + 6Cl⁻ = 2Al³⁺ + 6Cl⁻ + 3H2O
Al2O3 + 6H⁺ = 2Al³⁺ + 3H2O