If 30 mL of 5.0 $\times$10^-⁴ M Ca(NO₃)₂ are added to 70 mL of 2.0 $\times$ 10^-⁴ M NaF,will a precipitate occur? (K_sp of CaF₂ = 4.0 $\times$ 10^-¹¹) A)No,because the ion product is greater than K_sp. B)Yes,because the ion product is less than K_sp. C)No,because the ion product is less than K_sp. D)Not enough information is given. E)Yes,because the ion product is greater than K_sp.

Question

Quizplus · Accepted Answer

First, we need to calculate the concentration of both Ca2+ and F- ions in the solution by using the given volumes and concentrations:
[Ca2+] = (30 mL) x (5.0 M Ca(NO3)2) / (100 mL) = 1.5 M
[F-] = (70 mL) x (2.0 M NaF) / (100 mL) = 1.4 M

Next, we use the ion product (Qsp) expression for CaF2:
Qsp = [Ca2+][F-]^2 = (1.5 M)(1.4 M)^2 = 2.94

Comparing Qsp to the given value of Ksp (4.0 x 10^-11) for CaF2, we see that Qsp is much greater than Ksp, which means that the solution is supersaturated and a precipitate of CaF2 will form. Therefore, the correct answer is (C) No, because the ion product is less than Ksp.

If 30 ML of 5 ×\times× 10-4 M Ca(NO3)2 Are Added to 70 ML of 2

If 30 ML of 5 $\times$ 10^-⁴ M Ca(NO₃)₂ Are Added to 70 ML of 2