Question

why does the solubility of glauber salt first increases and then decreases

Answer 1

Answer:

The solubility first increases up to 32.4 0C, then decreases. This is due to Sodium sulphate is a decahydrate complex i.e., has 10 water molecules for every molecule of sodium sulphate. That is why after that temperature the solubility decreases as it depends on the anhydrous sulphate.