Solubility Product Constant (Ksp):
simply the measure of solubility
The product of equilibrium concentrations
of positive and negative ions in a
saturated solution of a dissolved salt
is called solubility product constant.
Ag Cl (s) ⥨ Ag+ + Cl–
Consider a saturated solution of a sparingly soluble salt AgCl . A dynamic equilibrium is established b/w the undissolved salt & its dissociated positive &negative ions in the solution. i.e.
Ag Cl (s) ⥨ Ag+ + Cl –
From law of mass action , we have
From law of mass action , we have
Kc = [Ag+] [ Cl- ]/ [ AgCl ]
Kc [AgCl ]= [Ag+] [ Cl- ]
Kc x K= [Ag+] [ Cl- ]
Ksp= [Ag+] [ Cl- ]
As Ag Cl is a solid & its concentration
remains constant due to very
light dissociation, so we can write as: