Question

A certain mass of calcium fluoride is added to water. The solution becomes cloudy, then clear as you see solid particles sink to the bottom of the container. Select all below that apply.

a. The solution is unsaturated
b. The solution is supersaturated
c. There are F⁻ions in solution.
d. The solution is saturated.
e. There are Ca²⁺ions in solution.

Answer 1

Initially, the solution of calcium fluoride in water was unsaturated, but as solids began to settle, it became saturated, confirming the presence of both F- and Ca^2+ ions in the solution.

Step-by-step explanation:

When a certain mass of calcium fluoride is added to water and the solution becomes cloudy before clearing and allowing solid particles to sink, we can interpret the outcomes related to saturation. Initially, the solution could have been unsaturated (a) if the calcium fluoride (CaF2) was initially dissolving. Eventually, as solids begin to settle at the bottom, it suggests that the solution reached its maximum capacity to hold solute, becoming saturated (d). We can confirm the presence of F− ions (c) in solution because CaF2 dissociates to form Ca^2+ and F− ions. Similarly, the presence of Ca^2+ ions (e) is confirmed by the same dissociation process. A supersaturated solution (b) is not a likely scenario since no conditions were described to create such a state (such as lowering the temperature after dissolving excess solute).