solubility product - Ksp
- equals product of ion concentrations raised to the power of their coefficients
- can be used to calculate solubility (g/L)
Find the Ksp for a saturated solution of Mg(OH)2 if the pH is 10.17
- assume that Mg(OH)2, a strong base, dissociates completely
- Mg(OH)2 >> Mg2+ + 2OH-
- pOH = 14 - pH = 14 - 10.17 = 3.83
- [OH-] = 10-pOH = 10-3.83 = 1.48 x 10-4
- [Mg2+] = [OH-] / 2 = 7.4 x 10-5
- Ksp = [Mg2+] [OH-]2 = 1.62 x 10-12
Find the molar solubility of Mn(OH)2 if the Ksp is 1.6 x 10-13
- Mn(OH)2 >> Mn2+ + 2OH-
- Ksp = [Mn2+] [OH-]2
- let c = molar solubility, concentration of Mn
- Ksp = c x (2c)2 = 4c3
- 1.6 x 10-13 = 4c3
- c = 3.4 x 10-5
Find the molar solubility of Ba(IO3)2 in a solution of 0.010 M NaIO3
- Given:
- Ksp = 6 x 10-10
- [IO3-] = [NaIO3] = 0.010
- Ksp = [Ba2+] [IO3-]2
- 6 x 10-10 = [Ba2+] (0.010)2
- [Ba2+] = molar solubility = 6 x 10-6
Find the molar solubility of Ba(IO3)2 in a solution of 0.01 M NaNO3
- Given:
- Ksp = 6 x 10-10
- NaNO3 has no effect on the solubility of Ba(IO3)2
- Ksp = [Ba2+] [IO3-]2
- let c = molar solubility, concentration of Ba
- Ksp = c x (2c)2 = 4c3
- 6 x 10-10 = 4c3
- c = 5.3 x 10-4