Solubility Product Constant

Definition

The equilibrium constant marking the condition where the dissolved state and the solid state balance one another thermodynamically.

Ksp is determined experimentally by finding the concentration at which dissolution and precipitation are in equilibrium on average. Below it the dissolved state is favored, at it the two states balance, and above it precipitation becomes favorable. Crossing Ksp does not cause scale; it grants permission, because what happens next depends on probability, organization, and time. A key limitation is that Ksp is defined in terms of ion activity, not concentration.

Related concepts

Gibbs Free Energy in Scaling · Supersaturation · Scale Indices

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Part of The Blueprint of Water · 🔥 thermodynamics