Warning: Copper compounds are toxic. Do not eat or drink. Hydrochloric acid is corrosive. Wear gloves.
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Copper(II) chloride forms chloro complexes with hydrochloric acid. They range in color from green to yellow. Add hydrochloric acid to a copper(II) chloride solution. It will turn yellow. This is the CuCl4(2-) ion. When diluted with enough water, it will form the normal Cu(H2O)(2+) ion again, which is green-blue.