Applications of Equilibrium
Solubility
One important application of Equilibrium is Solubility Equilibrium which
is also called Ksp. It is used when dealing with insoluble/sparingly
soluble salt solutions
Remember that salts disassociate into their
respective ions when they dissolve.
Example 1
Disassociate the following salts and write the K expression for the salt
solutions.
K
KBr(s)
P2S5(s) 
K2Cr04(s) 
Al2(CO3)3(s) 
NH4Cl(s) 
(NH4)2SO4(s) 
Molar Solubility
= x in the ICE table
= the # of moles of the solid that will
dissolve in a given volume
There are four types of equilibrium problems that we will be solving:
Type 1- Solve for Ksp
A saturated solution of Ag2CO3 can be made by dissolving 1.27 x 10-3 mol
of solid silver carbonate in 10.0 L of water. What is the Ksp for Ag2CO3?
Type 2- Solve for Molar Solubility/Concentration of the Ions in
Solution
What is the molar solubility of Ba(OH)2 if the Ksp is 2.22 x 10-2 at 15oC?
Common Ion Effect=
A reduction in a solubility of a salt caused by
the presence of another salt having a
common(the same) ion.
Type 3- Determining the solubility of a salt when a Common Ion is
present
The Ksp for PbCrO4 (s) is 2.3 x 10 -13. Determine the solubility of PbCrO4
(s) in a 0.10 mol/L solution of Na2CrO4 (aq).
Step 1- Disassociate the Soluble salt and determine the concentrations
of all of the ions.
Remember the balanced equation tells you the number of
moles/concentrations involved in a reaction
Step 2- Set up an ICE table
Step 3- Write the Ksp expression and sub in the equilibrium
concentrations solve for x (molar solubility of PbCrO4 (s)).