Can a precipitate dissolve upon addition of a diluted acid?
Another example of a precipitate dissolving in acid is the reaction $\ce{AgNO3 + HCl -&gt; AgCl (v) + HNO3}$. At first, the silver chloride precipitates out as a white powder (if kept away from direct light). Adding more acid, though, forms ligands with the additional chlorine ions:  $\ce{AgCl(s) + Cl- (aq) -&gt; AgCl2- (aq)}$. See also Physics Forums.