Problem: The Ksp of CaF2 at 25 °C is 4 x 10-11. Consider a solution that is 1.0 x 10-4 M Ca(NO3)2 and 2.0 x 10-4 M NaF.a. Q = Ksp and a precipitate will not form.b. Q > Ksp and a precipitate will form.c. Q > Ksp and a precipitate will not form.d. Q < Ksp and a precipitate will form.e. Q < Ksp and a precipitate will not form.

FREE Expert Solution

We’re being asked to determine if a precipitate will form in a solution that is 1.0 x 10-4 M Ca(NO3)2 and 2.0 x 10-4 M NaF.


For this, we need to compare the reaction quotient (Q) vs. the solubility product constant (Ksp)

Recall that when:

• Q > Ksp: the solution is supersaturated and a precipitate will form. Reactants are favored.

• Q = Ksp: the solution is at equilibrium and no precipitate will form.

• Q < Ksp: the solution is unsaturated and no precipitate will form. Products are favored.


The expected precipitate is CaF2. The dissociation of CaF2 in water is as follows:

CaF2(s)  Ca2+(aq) + 2 F(aq)


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Problem Details

The Ksp of CaF2 at 25 °C is 4 x 10-11. Consider a solution that is 1.0 x 10-4 M Ca(NO3)2 and 2.0 x 10-4 M NaF.

a. Q = Ksp and a precipitate will not form.
b. Q > Ksp and a precipitate will form.
c. Q > Ksp and a precipitate will not form.
d. Q < Ksp and a precipitate will form.
e. Q < Ksp and a precipitate will not form.

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Ksp concept. You can view video lessons to learn Ksp. Or if you need more Ksp practice, you can also practice Ksp practice problems.

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Based on our data, we think this problem is relevant for Professor Hoffman's class at UH.