Solubility Product and Common Ion Effect
The solubility product Ksp is the equilibrium constant for dissolution of a sparingly soluble salt, and added common ions suppress its solubility.
What is Solubility Product and Common Ion Effect?
The solubility product Ksp is the equilibrium constant for dissolution of a sparingly soluble salt, and added common ions suppress its solubility.
Key formula / rule: Precipitation occurs when the ionic product exceeds Ksp.
Key points
- Compute solubility from Ksp for salts of different stoichiometry.
- Evaluate whether precipitation occurs in a mixed solution.
Common exam trap
Equating solubility directly with Ksp regardless of stoichiometry.
Definitions
- Term
Solubility Product and Common Ion Effect
- Meaning
The solubility product Ksp is the equilibrium constant for dissolution of a sparingly soluble salt, and added common ions suppress its solubility.
- Term
Solubility Product and Common Ion Effect — explanation
- Meaning
Comparing the ionic product with Ksp predicts precipitation. The common ion effect is Le Chatelier's principle applied to a dissolution equilibrium.
Learning objectives
Compute solubility from Ksp for salts of different stoichiometry.
Evaluate whether precipitation occurs in a mixed solution.
Formulae
- Key point
Precipitation occurs when the ionic product exceeds Ksp.
- Key point
Solubility and Ksp are related through the salt's stoichiometry.
- Key point
A common ion decreases solubility without changing Ksp.
Prerequisites
CHE-U1-EQ-T1-S2-C1
Common mistakes
Equating solubility directly with Ksp regardless of stoichiometry.
Assuming Ksp changes when a common ion is added.
Keywords
Solubility
Product
Common
Effect
Practice preview
When a small amount of NaCl is added to a saturated solution of AgCl, what happens to the solubility of AgCl?…
easy
The solubility of CaF2 in water at 25 degrees C is 2.0 x 10^-4 mol/L. What is its solubility product (Ksp)?…
medium
A solution is prepared by mixing equal volumes of 2.0 x 10^-3 M BaCl2 and 4.0 x 10^-3 M Na2SO4. If Ksp for BaSO4 is 1.1 x 10^-10, will a precipitate form?…
medium