Advanced Placement (AP) Chemistry Practice Exam

The solubility product constant (Ksp) is specifically used to describe the equilibrium state of a sparingly soluble ionic compound when it dissolves in water. It expresses the relationship between the concentrations of the ions produced when the ionic compound dissociates in a saturated solution at equilibrium. This means that Ksp quantifies how much of the solid ionic compound can dissolve before the solution becomes saturated, leading to a dynamic equilibrium between the solid and its dissolved ions.

In the context of Ksp, each ionic species contributes a specific exponent based on the stoichiometry of the dissolution reaction. For example, for a generic salt \(A_mB_n\) that dissociates into \(m\) ions of \(A\) and \(n\) ions of \(B\), the Ksp expression would be written as:

\[ K_{sp} = [A]^m[B]^n \]

where \([A]\) and \([B]\) are the molar concentrations of the ions at equilibrium. Thus, Ksp is a vital concept in determining solubility and understanding the behavior of ionic compounds in solution.

The other options do not accurately define Ksp. For instance, while the rate of reaction in saturated solutions pertains to