Frequently Asked Questions

Ksp, the solubility product constant, is the equilibrium constant for the dissolution of a sparingly soluble ionic compound into its ions — a larger Ksp means the salt is more soluble.

Molar solubility (s) is the maximum number of moles of a salt that can dissolve per liter of solution before the solution becomes saturated.

For a salt AₓBᵧ that dissociates into xAⁿ⁺ + yBᵐ⁻, x and y are the number of cations and anions produced per formula unit — read directly from the subscripts in the chemical formula.

Ksp = x^x · y^y · s^(x+y), derived from substituting [A] = xs and [B] = ys (from the ICE table) into the Ksp expression Ksp = [A]^x[B]^y.

Look at the chemical formula's subscripts — for example, Ca(OH)₂ has x=1 (one Ca²⁺) and y=2 (two OH⁻); Ag₂CrO4 has x=2 (two Ag⁺) and y=1 (one CrO4²⁻).

Only a 1:1 salt (x=1, y=1) simplifies to s = √Ksp. Any other stoichiometry needs the general power relationship, since the coefficients from each ion's concentration multiply differently.

Yes — like all equilibrium constants, Ksp values are temperature-dependent. Tabulated Ksp values are typically reported at 25°C unless stated otherwise.

This calculator assumes the salt dissolves in pure water with no other source of the same ions. The common ion effect (a shared ion already present) reduces actual solubility below what this simple formula predicts.

Yes — Ksp values for sparingly soluble salts are often extremely small (10⁻¹⁰ or smaller), so the calculator displays results in scientific notation for readability.

Yes, completely free with no sign-up, and it runs entirely in your browser.