Сa + 2HCl = CaCl2 + H2↑
Ca + 2H⁺ + 2Cl⁻ = Ca²⁺ + 2Cl⁻ + H₂↑
Ca + 2H⁺ = Ca²⁺+H₂↑
SO3 + H2SO4 ≠
Ag + HCl ≠
Na2S + 2HNO3 = 2NaNO3 + H2S↑
2Na⁺+S²⁻ + 2H⁺ + 2NO₃⁻ = 2Na⁺+2NO₃⁻ + H₂S↑
2H⁺ + S²⁻ = H₂S↑
2KOH + SO3 = K2SO4 + H2O
2K⁺+ 2OH⁻ + SO₃ = 2K⁺ + SO₄²⁻ + H₂O
2OH⁻+SO₃ = SO₄²⁻ + H₂O