---
title: "A student investigates the dissolution of calcium fluoride, \\(\\text{CaF}_2\\text{(s)}\\), at \\(25\\ ^\\circ\\text{C}\\). The dissolution process is represented by the following equilibrium equation:  \\[ \\text{CaF}_2\\text{(s)} \\rightleftharpoons \\text{Ca}^{2+}\\text{(aq)} + 2\\,\\text{F}^-\\text{(aq)} \\]  The student compares the molar solubility of \\(\\text{CaF}_2\\) in pure distilled water with its molar solubility in a \\(0.10\\text{ M }\\text{NaF(aq)}\\) solution at the same temperature. Which of the following statements best compares the molar solubility of \\(\\text{CaF}_2\\) in \\(0.10\\text{ M }\\text{NaF(aq)}\\) with its molar solubility in pure water and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/121389/"
date_modified: "2026-08-23T05:02:02+00:00"
---

# A student investigates the dissolution of calcium fluoride, \(\text{CaF}_2\text{(s)}\), at \(25\ ^\circ\text{C}\). The dissolution process is represented by the following equilibrium equation:

\[ \text{CaF}_2\text{(s)} \rightleftharpoons \text{Ca}^{2+}\text{(aq)} + 2\,\text{F}^-\text{(aq)} \]

The student compares the molar solubility of \(\text{CaF}_2\) in pure distilled water with its molar solubility in a \(0.10\text{ M }\text{NaF(aq)}\) solution at the same temperature. Which of the following statements best compares the molar solubility of \(\text{CaF}_2\) in \(0.10\text{ M }\text{NaF(aq)}\) with its molar solubility in pure water and provides the correct justification?

A student investigates the dissolution of calcium fluoride, \(\text{CaF}_2\text{(s)}\), at \(25\ ^\circ\text{C}\). The dissolution process is represented by the following equilibrium equation:

\[ \text{CaF}_2\text{(s)} \rightleftharpoons \text{Ca}^{2+}\text{(aq)} + 2\,\text{F}^-\text{(aq)} \]

The student compares the molar solubility of \(\text{CaF}_2\) in pure distilled water with its molar solubility in a \(0.10\text{ M }\text{NaF(aq)}\) solution at the same temperature. Which of the following statements best compares the molar solubility of \(\text{CaF}_2\) in \(0.10\text{ M }\text{NaF(aq)}\) with its molar solubility in pure water and provides the correct justification?

- **A.** It is greater in \(0.10\text{ M }\text{NaF(aq)}\) because the spectator \(\text{Na}^+\text{(aq)}\) ions stabilize dissolved \(\text{Ca}^{2+}\text{(aq)}\) cations, shifting the equilibrium toward products.
- **B.** It is lower in \(0.10\text{ M }\text{NaF(aq)}\) because the presence of the common ion \(\text{F}^-\text{(aq)}\) shifts the dissolution equilibrium toward the solid reactant.
- **C.** It is lower in \(0.10\text{ M }\text{NaF(aq)}\) because the addition of \(\text{F}^-\text{(aq)}\) ions decreases the value of the solubility product constant, \(K_{sp}\).
- **D.** It is greater in \(0.10\text{ M }\text{NaF(aq)}\) because the higher concentration of \(\text{F}^-\text{(aq)}\) increases the rate of the forward dissolution reaction.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121389/*