Which change will alter the value of Ksp for the salt AgN3?

• A. Adding water to the solution.
• B. Increasing the temperature of the solution.
• C. Removing azide ions from the solution.
• D. Adding silver ions to the solution.

Answer: (B)

Ksp is an equilibrium constant for the dissolution of a sparingly soluble salt, here AgN3. For AgN3(s) ⇌ Ag+(aq) + N3−(aq), Ksp = [Ag+][N3−]. At a given temperature, this product has a fixed value. Changing temperature alters that constant, because temperature affects the extent to which the solid dissolves. Dissolution is typically endothermic, so raising temperature increases the dissolution tendency and thus increases Ksp.

Adding water just dilutes the ions; the system re-establishes equilibrium at the same Ksp for that temperature, so the constant itself doesn’t change. Removing azide ions or adding silver ions shifts the equilibrium position (and solubility) via Le Chatelier’s principle, but the numerical value of Ksp remains tied to the temperature. Therefore, the change that alters Ksp is increasing the temperature.