Posted by Ashley on .
Consider a saturated solution of calcium fluoride in 0.086 M potassium nitrate. Complete the following tasks, and then answer the question.
a) Write the chemical equation corresponding to Ksp.
b) Write the defining expression for the thermodynamic solubility product constant, Kspo.
c) Write the defining expression for the conditional solubility product constant, Ksp'.
d) For the Ca2+ and F- ions, write the mathematical relations defining activity of each ion in terms of its concentration and activity coefficient.
e) Based on your answers above, derive a relationship for Ksp' in terms of Kspo and activity coefficients, and calculate the value of Ksp', given that Kspo = 3.9 x 10-11. (Note: Compute the activity coefficient for each ion using the Debye-Huckel equation. You can disregard the contribution of the dissolved CaF2 to the overall ionic strength. Also disregard the formation of any HF in the equilibrium solution.)
Calculate the molar solubility of the calcium fluoride.