Answer: Option (a) is the correct answer.
Explanation:
An unsaturated solution is a solution in which solute particles completely dissolve into the solvent.
And, in order to increase the rate of dissolution of an unsaturated solution we can increase the temperature. Hence, there will be increase in kinetic energy of molecules which will lead to more number of collisions.
Thus, it will eventually lead to increase in rate of dissolution.
Thus, we can conclude that increasing the temperature is the factor which increases the rate of dissolution in an unsaturated solution.
