The following is a thought experiment. Imagine that you put a little water in a test tube and add some NaF crystals. Immediately after you add NaF, you observe that the crystals begin dissolving. The quantity of solid NaF decreases, but before long, it appears that no more NaF is dissolving. The solution is saturated.

(a) The equation for the dissolution of NaF in water is NaF(s) → Na⁺(aq) + F^–(aq). As NaF dissolves, what do you think happens to the rate of dissolution? Describe what is occurring on the molecular level.

(b) Assume that the reverse reaction, Na⁺(aq) + F^–(aq) → NaF(s), also occurs as the crystal dissolves. In other words, both dissolution and precipitation are taking place. When it appears that there is no more change in the quantity of NaF dissolving (the solution is saturated), what has happened to the rates of the forward and reverse reactions? Explain your answer.