How to know when dissolution is complete? In a given solubility equilibrium, I know that if $ Q &gt;K_s$, then the salt will precipitate until $ Q =K_s$. If $ Q &lt;K_s$, however, would the precipitate dissolve until $ Q =K_s$ too?
You've described the general tendency for any equilibrium process, including solubility. So, the short answer is yes, you will dissolve more until the reaction quotient is equal to the equilibrium constant.