The Solubility Product ($K_{sp}$) defines the equilibrium state for a saturated solution of a sparingly soluble salt.

• Ionic Product ($I.P.$) is the product of concentrations of ions at any given moment.

1. $I.P.<K_{sp}$: Solution is unsaturated. No precipitation.
2. $I.P.=K_{sp}$: Solution is exactly saturated. No precipitation.
3. $I.P.>K_{sp}$: Solution is supersaturated. Precipitation will occur until $[I.P.]$ returns to $[K_{sp}]$.

• This principle is fundamental to quantitative separation of groups in salt analysis.