A solution containing sodium fluoride is mixed with one containing calcium nitrate to form a solution that is 0.015 M in NaF and 0.010 M in Ca(NO₃)₂. Does a precipitate form in the mixed solution? If so, identify the precipitate.

Verified step by step guidance

1. Identify the possible precipitate by considering the ions present: Na^+, F^-, Ca^{2+}, and NO_3^-. The potential precipitate is CaF_2, as it is insoluble in water.
2. Write the balanced chemical equation for the formation of the precipitate: Ca^{2+} (aq) + 2F^- (aq) \(\rightarrow\) CaF_2 (s).
3. Determine the solubility product constant (K_{sp}) for CaF_2 from a reliable source.
4. Calculate the ion product (Q) for CaF_2 using the concentrations of Ca^{2+} and F^- in the mixed solution: Q = [Ca^{2+}][F^-]^2.
5. Compare the ion product (Q) to the solubility product constant (K_{sp}): If Q > K_{sp}, a precipitate will form; if Q < K_{sp}, no precipitate will form.

Key Concepts

Solubility Product Constant (Ksp)

The solubility product constant (Ksp) is a numerical value that represents the extent to which a compound can dissolve in water. It is specific to each ionic compound and is determined at a given temperature. When the product of the concentrations of the ions in a solution exceeds the Ksp, a precipitate will form, indicating that the solution is supersaturated.

Ionic Equilibrium

Ionic equilibrium refers to the balance between the dissolved ions in a solution and the solid phase of a compound. In the context of precipitation reactions, it is essential to understand how the concentrations of ions change when two solutions are mixed, and how these changes can lead to the formation of a solid precipitate if the ionic product exceeds the Ksp.

Common Ion Effect

The common ion effect describes the decrease in solubility of an ionic compound when a common ion is added to the solution. In this scenario, the presence of fluoride ions from sodium fluoride can affect the solubility of calcium fluoride (CaF2) if it forms, leading to a potential precipitate. Understanding this effect is crucial for predicting whether a precipitate will form when mixing solutions.