Simulation · Chemistry · Class 11
Which salt dissolves more?
From the lesson Solubility equilibria of sparingly soluble salts in Equilibrium. Change the values and watch what happens.
Which salt dissolves more?Chemistry · Class 11
The idea behind it
NCERT § "Solubility Equilibria of Sparingly Soluble Salts"
- For a sparingly soluble salt in contact with its saturated solution, the product of ion concentrations, each raised to its stoichiometric power, is the solubility product Ksp.
- For BaSO₄ ⇌ Ba²⁺ + SO₄²⁻, Ksp = S² where S is the molar solubility.
- For a general salt MₓXᵧ, Ksp = xˣ yʸ S^(x+y); for M₂X, Ksp = 4S³, and for MX₂ (like CaF₂), also 4S³.
- If the ionic product in a solution exceeds Ksp, precipitation occurs; if it is less, the solution is unsaturated and more solid can dissolve.
- A common ion lowers the solubility of a sparingly soluble salt; this is used to purify common salt by passing HCl gas through its saturated solution, which precipitates NaCl.
- Salts of weak acids become more soluble at lower pH, because the anion is removed by protonation.
- Compare the solubility of salts by comparing S, not Ksp directly, unless they have the same formula type.