Here is a note on glauber's salt and ammonium sulfate, which are sometimes found in wastewater from chemical plants. Sodium sulfate is the IUPAC name , and sodium sulfate decahydrate is called sodium glauber. A solution of sodium hydroxide neutralized with sulfuric acid yields crystals of sodium sulfate decahydrate. NaOH + H2SO4 -> Na2SO4 + 2H2O The solubility curve of sodium sulfate is bent at 32.4°C as shown in the figure below*1, and this point is called the transition point. Solubility of sodium sulfate (water) *1) The solubility of sodium sulfate increases with increasing temperature up to 32.4℃, but decreases above 32.4℃. This is because the solubility of the hydrate is -56.0 kJ (endothermic), while the heat of dissolution of the anhydride is +2.34 kJ (exothermic). Ammonium sulfate i...