Layers of copper (I), copper (II) and hydrogen peroxide

This experiment shows formation of a dark compound on reaction between a solution, containing a lot of copper (I) and hydrogen peroxide. The copper (II) formed from the copper (I) and the hydrogen peroxide reacts and forms a dark compound at the layer, where hydrogen peroxide and acidic copper (I) liquid diffuse into each other.

The following steps were performed:

1. Prepare a solution of CuCl2.2H2O in concentrated HCl.
2. Add ascorbic acid in small amounts and with some heating in order to increase speed of dissolving of the solid. At first, the liquid becomes very dark, almost black. When more ascorbic acid is added, however, the liquid becomes lighter again. In this experiment ascorbic acid was added, such that the liquid is fairly light yellow brown.
3. Carefully pour a 5% solution of H2O2 on the liquid, taking care that the liquids do not mix up completely.
4. Let test tube stand for a while and observe what happens.

The result is shown in the following two pictures.

These two pictures were taken with an interval of time of 2 minutes between them.

The lower layer is the original solution with copper (II) chloride, ascorbic acid and HCl (30%).

The dark layer on top of this is the dark compound formed on reaction of copper (I) and copper (II). The copper (II) is formed from copper (I) and H2O2.

The green layer, which becomes lighter and more blue, when going upwards is due to copper (II), mixed with H2O2 and HCl.

The colorless layer at the top is 5% H2O2.

The situation is very stable. Even after 10 minutes hardly changes can be observed. After that time, patience was exhausted and the liquid was shaked carefully. The result is shown here. The picture is taken immediately after shaking. It shows a small amount of the original light brown liquid, covered by green H2O2/Copper (II)/dilute HCl.