Химическая ципочка Na-NaOh-Na2SO4-?-NaCL-NA-NO3
2Na + 2H2O = 2NaOH + H2 2NaOH + H2SO4 = Na2SO4 + 2H2O Na2SO4 + BaCl2 = BaSO4 + 2NaCl NaCl + AgNO3 = AgCl + NaNO3.