Na2O-NaOH-NaHSO4-Na2SO4-SO3 Уравнение реакций
Na2O + H2O = 2NaOH NaOH + H2SO4 = NaHSO4 + H2O NaHSO4 + NaOH = Na2SO4 + H2O Na2SO4 =(t) Na2O + SO3