Question

How to make a saturated solution of sodium chloride?

Answer 1

Hint:The ability of a solute to be dissolved in a solvent is called solubility. A solution is said to be saturated if we cannot dissolve more solute to the solution. This is an equilibrium condition.

Complete step by step answer:Sodium chloride solution can be prepared by dissolving the sodium chloride crystals in water. For every solution, there is a saturation point after which no solute can be dissolved in the solution. When a solution reaches this saturation point, the solution is said to be saturated. A saturated solution of sodium chloride is when we cannot dissolve more sodium chloride in the solution. In this condition, an equilibrium will be established between the solution and the undissolved solute.
The solubility of any solute in a solvent depends on the temperature. The solubility of sodium chloride in water is $35g/100mL$ approximately. This data is valid only at a temperature of ${20}^{0}C$ . Adding more sodium chloride than $35g$ at this temperature will give a saturated solution of sodium chloride. Hence we can prepare a saturated solution of sodium chloride by adding approximately $40-45g$ of sodium chloride in $100mL$ water. Doing so, some amount of sodium chloride will remain undissolved in the solution. On filtration or decantation of this solution we will get a saturated solution of sodium chloride.

Note:
If we heat the above solution, the undissolved sodium chloride will also be dissolved in the solution. Then we cannot say the solution is saturated. We need to dissolve more solute to get a saturated solution. Saturated solution on cooling becomes supersaturated.