Solubility Product Constant (Ksp)
Search one salt for a full Ksp breakdown, or paste/upload several salts to compare ideal molar solubility and saturated ion concentrations in pure water.
Solubility Product Constant Ksp
General Chemistry • Solubility and Complex Ion Equilibria
Frequently Asked Questions
What is the solubility product constant (Ksp)?
Ksp is an equilibrium constant for the dissolution of a sparingly soluble ionic solid. It relates the equilibrium ion concentrations to the stoichiometric powers in the dissolution reaction.
How do you calculate molar solubility from Ksp?
Write the dissolution reaction and express ion concentrations in terms of the molar solubility s. Substitute into the Ksp expression and solve for s; the power of s depends on the reaction stoichiometry.
Why can’t I compare Ksp values directly for different salts?
Different salts produce different numbers of ions and different exponents in the Ksp expression, so the same Ksp magnitude can correspond to very different solubilities. Comparing molar solubility s is more meaningful across different stoichiometries.
Does this calculator include the common ion effect or pH effects?
No, the solubility estimate is for ideal molar solubility in pure water. Common ions, pH changes, and complex ion formation can change solubility and require a different equilibrium setup.
At what temperature are the Ksp values given?
The tabulated Ksp values shown by the calculator are given at 25 C. Ksp can change with temperature, so values at other temperatures may differ.