Question

Assertion: A supersaturated solution crystallizes as it cools.
Reason: The solubility increases as the temperature decreases
A) Both assertion and reason are correct and reason is the correct explanation of assertion
B) Both assertion and reason are correct and reason is not the correct explanation of assertion
C) Assertion is wrong and reason is correct
D) Both assertion and reason are wrong

Answer 1

Hint: A saturated solution is that which contains as much of solute as it can dissolve at that temperature.

Complete answer
Supersaturation is a state of a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances.
OR supersaturated solution is that in which more amount of solute is dissolved than it can dissolve at that temperature.
Since a supersaturated solution contains more amount of solute than it can dissolve at that temperature, it is prepared by heating the solvent and then dissolving the solute. It crystallizes as the solution cools. As temperature is increased, more solute is dissolved in the solvent than it can at room temperature. The excess of solute comes out of the solution and crystallizes as the solution is cooled.
Depending on the type of solute, some solutes solubility increases as the temperature increases and for some solutes solubility decreases as temperature increases. This is not connected to crystallization of supersaturated solutions.
Hence, assertion and reason are correct. Reason is not the correct explanation of assertion.

So, the correct option is B

Note:
Calcium sulphate is an example of a salt whose solubility decreases with increase in temperature. An unsaturated solution is that which can dissolve more of the solute.