2Na + 2HCl = 2NaCl + H₂↑CuO + 2HCl = CuCl₂ + H₂OZn + 2HCl = ZnCl₂ + H₂↑Fe₂O₃ + 6HCl = 2FeCl₃ + 3H₂OSO₂ + HCl --> ClSO₂HNaOH + HCl = NaCl + H₂O