Question

Why does hot saturated solution of potassium nitrate forms crystal on cooling?

Answer 1

• A solution that can not dissolve any more of the solute at a given temperature is called a saturated substance.
• The solubility of potassium nitrate$\left({\mathrm{KNO}}_3\right)$ increases with an increase in temperature and decreases with a decrease in temperature.

• The solubility of potassium nitrate decreases with the fall in temperature. Thus, on cooling a saturated solution of potassium nitrate the excess of it separates from the solution, in the form of crystals.