Answer:
addition of aqueous hydrochloric acid
Step-by-step explanation:
The solubility of copper (ll) hydroxide in water is negligible. This implies that the substance is only slightly soluble in water.
However, the addition of aqueous hydrochloric acid leads to the following reaction;
Cu(OH)2 + 2HCl ---------> CuCl2 + 2H2O
Copper II chloride is soluble in water hence the crystals dissolve when stirred. and the molar solubility increases.