Question

Deepti wanted to dissolve more sugar to an already saturated solution of sugar in a bottle. What can she do to add more sugar to it?

• A. Decrease the temperature of the solution
• B. Increase the temperature of the solution
• C. Dilute the solution by adding more water
• D. Just add sugar and stir

Answer 1

Answer: (B), (C)

The correct options are
B

Increase the temperature of the solution

C

Dilute the solution by adding more water

A saturated solution cannot dissolve more solute in it. To dissolve more solute in it, the solubility must be increased. This can be done by heating the solution.

• For most solutes, solubility increases with an increase in temperature. If she somehow makes the solution unsaturated, then she can dissolve more solute in it.
• One way is to add more solvent to the solution. By adding more solvent, the volume of the solution increases but not the mass of solute dissolved. As such the concentration of solution decreases i.e it becomes unsaturated and more solute can be added to it.
• Also, by increasing the pressure of the gas in the bottle more solute can be added. This is because solubility increases with an increase in pressure. The best example is an aerated drink like Pepsi. Carbon dioxide is dissolved in it at higher pressure. This is why, when you open the bottle, the pressure becomes less. As a result solubility decreases and dissolved carbon dioxide is released from the solution, which can be seen as the 'fizz'.