Warning: Copper(I) chloride is toxic. Do not eat the precipitate or drink the solutions. Otherwise, everything is safe.
This is the beginning of the copper(II) chloride series of experiments. A wide range of experiments with copper(II) chloride can be done by the home chemist. Information on how to make copper(II) chloride can be found here: http://lanthanumkchemistry.over-blog.com/article-how-to-make-copper-ii-chloride-76079848.html
You will need:
Ascorbic acid (found as Vitamin C crystals)
Previously made copper(II) chloride
Filter paper, tissues, or coffee filter paper
3% hydrogen peroxide, optional
Dissolve a small amount of copper(II) chloride in water. Add ascorbic acid. A color change from blue to green to a white precipitate is observed. This white precipitate is copper(I) chloride. Filter it. Copper(I) chloride is easily oxidized by air. Within a few minutes of being in air, the filter paper should start turning green again. Before it dries, it will be completely green. When I conducted this experiment, the copper(I) chloride took about 10 minutes to begin turning green. Make another small batch. Filter and let it dry until it just starts turning green. Add hydrogen peroxide to the filter paper. It should immediately turn green. The hydrogen peroxide oxidizes the copper(I) chloride to copper(II) chloride and copper(II) hydroxide. Both of these chemicals are green or blue-green.
Here are pictures of the reaction and the resulting white precipitate. Asc stands for ascorbate, the part of the ascorbic acid that reduces the copper(II) to copper(I). H+ stands for the acid part of ascorbic acid, which makes the solution turn greenish.
Method 2: Dissolve copper(II) chloride crystals in concentrated hydrochloric acid. Add copper metal and heat. This comproportionation reaction will occur: CuCl2 + Cu --> 2 CuCl. Add sodium bicarbonate to the resulting dark solution until a pure white precipitate falls out. The leftover solution will probably be greenish as a result of excess copper(II) chloride. This white precipitate is copper(I) chloride.