Final answer:
The solubility of KCl in water decreases when a saturated solution in 100 grams of water is cooled from 80°C to 10°C, resulting in the formation of a precipitate.
Step-by-step explanation:
A saturated solution of potassium chloride (KCl) in water is a solution in which no more solute can dissolve at a given temperature. When a saturated solution of KCl in 100 grams of water is cooled from 80°C to 10°C, the solubility of KCl in water decreases. This means that the answer to the question is b) Decreased solubility of KCl in water. As the temperature decreases, the solubility of most solutes, including KCl, decreases. The excess solute that is no longer soluble will start to crystallize out of the solution, resulting in the formation of a precipitate.