Which statement is true about Ksp?

Which statement is true about Ksp?

• A. Ksp changes with ion concentrations in solution
• B. Ksp depends on the presence of common ions
• C. Ksp is constant for a given temperature
• D. Ksp depends on pressure for solids

Answer: (C)

Ksp is the solubility product constant for a dissolving solid in water, defined as the product of the ion concentrations at equilibrium raised to their stoichiometric powers. For a fixed temperature, that product has a single value. The solution adjusts the individual ion concentrations to meet that fixed product when it’s saturated, so changing how much solid is present doesn’t change Ksp; it only changes how much dissolves. Introducing a common ion shifts the equilibrium toward less dissolution, lowering solubility, but the numerical value of Ksp remains the same. Pressure changes for solids have negligible impact on the dissolution equilibrium, so Ksp stays constant with respect to pressure for a solid. Therefore, Ksp is constant for a given temperature.

Ksp is the solubility product constant for a dissolving solid in water, defined as the product of the ion concentrations at equilibrium raised to their stoichiometric powers. For a fixed temperature, that product has a single value. The solution adjusts the individual ion concentrations to meet that fixed product when it’s saturated, so changing how much solid is present doesn’t change Ksp; it only changes how much dissolves. Introducing a common ion shifts the equilibrium toward less dissolution, lowering solubility, but the numerical value of Ksp remains the same. Pressure changes for solids have negligible impact on the dissolution equilibrium, so Ksp stays constant with respect to pressure for a solid. Therefore, Ksp is constant for a given temperature.