To measure the total mass of a solute that can dissolve in a solvent
To determine the concentration of a solute in a saturated solution
To calculate the solubility of a solute in a given solvent
To compare the solubilities of different solutes in the same solvent
Explanation
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Discussions (2)
First, forget the options for a moment.
Ksp stands for solubility product constant.
Now let me translate that into normal language.
Ksp is used when a salt is slightly soluble in water and reaches a point where it can no longer dissolve more. At that point, the solution is called a saturated solution.
So what is happening in simple terms is this:
Some of the solid dissolves into ions. At the same time, those ions can recombine and form solid again. Eventually, a balance is reached where the rate of dissolving equals the rate of forming solid again. That is equilibrium.
Ksp is just a number that tells you how much of those ions exist in solution at that equilibrium point.
So in the simplest human language:
👉 Ksp is used to describe how soluble a slightly soluble salt is in water.
Now let’s carefully go through the options and remove confusion step by step.
Option A says it is used to measure the total mass of solute that can dissolve in a solvent. That sounds like solubility in a very rough sense, but Ksp is not about mass directly. It is not measuring grams that dissolve. It is dealing with ions in solution and equilibrium. So this is not accurate.
Option B says it is used to determine the concentration of a solute in a saturated solution. This one is closer. Because Ksp is definitely connected to concentration of ions when the solution is saturated. But the wording is a bit narrow and misleading because Ksp is not just about one solute concentration, it is about the relationship between ions in equilibrium.
Option C says it is used to calculate the solubility of a solute in a given solvent. This is actually the most correct and complete idea. Because from Ksp, you can calculate how much of a salt will dissolve before the solution becomes saturated. That is exactly what JAMB expects you to know.
Option D says it is used to compare solubility of different solutes. This can be done using Ksp values, yes, but that is not its main purpose. It is more of a secondary application, not the core definition.
Now let me bring everything together in a way that will make it stick.
Ksp is basically a tool chemists use to calculate solubility in saturated solutions. Once you know Ksp, you can work out how much of a salt dissolves before equilibrium is reached.
So the correct answer is C.
