chemistry

posted by .

What is solubility of CaF2 in a solution buffered at pH 5

  • chemistry -

    The acidity of the solution increases the solubility of CaF2 due to the formation of the weak acid, HF. The increase depends upon the pH, it may or may not be significant.
    The two equations are:
    CaF2 ==> Ca^+2 + 2F^-
    HF ==> H^+ + F^-

    Ksp = (Ca^+2)(F^-)^2
    Ka = (H^+)(F^-)/(HF).
    If (CaF2) = S, then (Ca^+2) = S and
    2(Ca^+2) = (F^-).
    2S = (F^-).

    Solve Ka for HF.
    (HF) = (H^+)(F^-)/Ka = (10^-5)(F^-)/Ka and rearrange to (HF) = some number*(F^-). Then
    2S = (F^-) + (HF). solve for (F^-) and plug all this into Ksp and you will have only one unknown, namely S.
    Post your work if you get stuck. Show what you are using for Ka and Ksp. Check my thinking.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chem/solubility

    the Ksp of CaF2 = 1.46*10^-10 and Ka of HF = 3.5*10^-4 Calculate the pH of a solution in which the solubility of CaF2 = .0100 moles/liter. so Ksp =[Ca2+][F-]^2 and Ka =[H3O+][F-]/[HF] I'm not sure how to continue...
  2. chemistry

    The mineral CaF2 has a solubility of 2.1 x 10^-4 M. What is the Ksp of CaF2?
  3. Chemistry

    What is the molar solubility of CaF2 if o,1o mol of NaF are added to 1.0L of a saturated solution of CaF2?
  4. Chemistry

    What is the molar solubility of Fe(OH)3(s) in a solution that is buffered at pH 2.75?
  5. chemistry

    What is the solubility of CaF2 in a buffer solution containing .30 M HCHO2 and .20 M NaCHO2?
  6. Chemistry

    Given a saturated solution of CaF2, write the ionic equilibrium and use it to calculate the solubility of CaF2. My answer for the ionic equation is CaF2(s)<->Ca2+(aq)+ 2F-(aq) Ksp= [Ca2+][F-]2 the given ksp is 3.32*10-4 how do …
  7. chemistry

    Given a saturated solution of CaF2, write the ionic equilibrium and use it to calculate the solubility of CaF2. My answers for the ionic equation and ksp values are CaF2(s)<->Ca2+(aq)+ 2F-(aq) Ksp= [Ca2+][F-]2 ksp=2.02*10^-4 …
  8. AP Chemistry

    A saturated solution of CaF2 (of MW 78.0 g/mol) contains 0.0167 grams per liter. What is the solubility product constant of CaF2?
  9. Chemistry

    How does the solubility of Mg(OH)2 in a buffered solution compare to the solubility of Mg(OH)2 in pure water?
  10. chemistry

    Given the following solubility constants, which list arranges the solutes in order of increasing solubility?

More Similar Questions