Question

Name one salt whose solubility first increases and then decreases with a rise in temperature.

Answer 1

• The solubility of a solute in a solvent at a given temperature is equivalent to the maximum number of grams of the solute needed to saturate 100 g of that solvent at that particular temperature.

The solubility of a particular solute in a solvent varies with temperature:-

• The solubility of a solid in a liquid generally increases with a rise in temperature but Glauber's salt $({\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O})$ shows an anomalous solubility curve.
• Solubility curve of Glauber's salt $({\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O})$ first increases until the temperature reaches 32.8^oC and then it falls slightly. This occurs because Glauber's salt $({\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O})$ is hydrous below 32.8^oC and becomes anhydrous above this temperature.
• The solubility of Glauber's salt $({\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O})$ first increases and then decreases with a rise in temperature.