If a compound is slightly soluble is it aqueous solution or solid?
If you're asking whether to write (aq) or (s) in a chemical reaction, it really depends on how much of it dissolves, which can be realized by calculating the solubility-product constant (
Some textbooks say they write (aq) instead of (s) if the solubility is greater than
If you're asking in terms of reality whether a slightly soluble compound is present as a solid or as dissolved ions, then the answer is, in essence, both.
Once a solution becomes saturated (when no more solute can dissolve in the solvent), the dissociation reaction has reached equilibrium. There is now an equal rate of the solid dissociating into ions, and ions recombining to form the solid.