Solubility Product (Ksp) Calculator
Molar solubility from Ksp, for any salt stoichiometry.
Work out Solubility Product (Ksp). Molar solubility from Ksp, for any salt stoichiometry. Free, with no account and nothing to download.
Scientific notation works — AgCl is 1.8e-10, CaF₂ is 3.9e-11.
AgCl is 1 and 1. CaF₂ is 1 and 2. Ag₂CrO₄ is 2 and 1.
Molar solubility
1.342e-5 M
Ksp = (1s)^1 · (1s)^1
Ksp values only rank solubility within the same formula type. CaF₂ has a smaller Ksp than AgCl — 3.9 × 10⁻¹¹ against 1.8 × 10⁻¹⁰ — yet it is about sixteen times more soluble, because the fluoride term is squared and that changes how the root works out. Comparing Ksp across different stoichiometries is one of the most common errors in the topic. Convert to molar solubility first, then compare.
How the Solubility Product (Ksp) Calculator works
Enter a Ksp and the ion counts in the formula and this returns the molar solubility along with each ion's concentration at saturation. It handles 1:1, 1:2, 2:1 and larger stoichiometries, which is where most Ksp mistakes actually happen.
Also known as: ksp calculator · molar solubility calculator · ksp to solubility converter · solubility product constant
Frequently asked questions
How do I calculate molar solubility from Ksp?
Write the dissolution equation, express each ion as a multiple of s, substitute into the Ksp expression and solve. For AgCl, Ksp = s², so s = √Ksp = 1.34 × 10⁻⁵ M. For CaF₂, Ksp = 4s³.
Does a smaller Ksp always mean less soluble?
Only when comparing salts with the same formula type. CaF₂ has a smaller Ksp than AgCl yet is about sixteen times more soluble, because the exponents in the two expressions differ. Convert both to molar solubility before comparing.
Why is Ksp temperature dependent?
Because it is an equilibrium constant, and every equilibrium constant shifts with temperature. Most salts dissolve endothermically and get more soluble when heated; a few, including calcium sulfate, do the opposite.
What does it mean if Q is greater than Ksp?
The solution is supersaturated and a precipitate should form. Q below Ksp means more can dissolve, and Q equal to Ksp is exactly saturated.
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