When Q > Ksp, the system will

• A. Form a precipitate.
• B. Dissolve more solid.
• C. Remain unchanged.
• D. Change temperature.

Answer: (A)

When the ion product Q is larger than the solubility product Ksp, the solution is supersaturated with respect to the solid. In this situation, the system shifts to reduce Q back toward Ksp by forming solid from the excess ions. That means ions combine to precipitate out of solution until the concentrations drop to the level defined by Ksp. So a precipitate forms.

The other possibilities don’t match this immediate behavior: dissolving more solid would increase Q further, not decrease it; the system isn’t in equilibrium, so it won’t remain unchanged; and changing the temperature is not the automatic response to Q > Ksp—the temperature could alter Ksp itself, but the precipitation reaction is the direct consequence of supersaturation.