Chemistry - Liquid Solution Question with Solution | TestHub

The dissolution of anhydrous sodium sulfate (${\mathrm{Na}}_2{\mathrm{SO}}_4$) in water is an exothermic process ($\Delta H<0$).

According to Le Chatelier's principle, for an exothermic dissolution, an increase in temperature shifts the equilibrium in the backward direction.

Thus, the solubility of ${\mathrm{Na}}_2{\mathrm{SO}}_4$ decreases with an increase in temperature.

For $\mathrm{NaCl}$, ${\mathrm{KNO}}_3$, and ${\mathrm{NaNO}}_3$, the dissolution is endothermic, so their solubility increases with an increase in temperature.

Answer: ${\mathrm{Na}}_2{\mathrm{SO}}_4$