Question

If $Xg$ of potassium nitrate is added to $100g$ of water at ${60^o}C$ and the salt dissolves completely then is the solution formed is saturated or unsaturated?

Answer 1

Hint: A saturated solution is a solution that is in equilibrium with respect to a given dissolved substance. A solution that is not in equilibrium with respect to a given dissolved substance and in which more substance can be dissolved is known to be an unsaturated solution.

Complete answer:
A solution which does not dissolve further amounts of a solute at a particular temperature is called a saturated solution. Solubility is the property of a solid, liquid or gaseous chemical substance called solute to dissolve in a solid, liquid or gaseous solvent. The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and presence of other chemicals (including changes to the pH) of the solution.
To determine the solubility of the $Xg$ of potassium nitrate in $100g$ of water at ${60^o}C$, the salt is added slowly in the water. After adding the salt to the water, the salt solution is stirred at the same temperature thoroughly. The $Xg$ of potassium nitrate is dissolved completely in the water. If we add more and more solute slowly, the water will keep dissolving the salt because of the high temperature of water. The solution is, therefore, known as an unsaturated solution.

Note:
The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.