WAEC - Chemistry (2020 - No. 35)
Which of the following statements about the solubility of a salt is correct?
A salt whose solubility increases with temperature would not crystallize easily on cooling
A salt whose solubility is independent of temperature would normally crystallize out on cooling
Crystallization would be efficient in separating out a salt whose solubility increases considerably with temperature
Solubility of a solid does not affect its crystallization
Explanation
Crystallization is based on the principles of solubility: compounds (solutes) tend to be more soluble in hot liquids (solvents) than they are in cold liquids. If a saturated hot solution is allowed to cool, the solute is no longer soluble in the solvent and forms crystals of pure compound.