Copper ii chloride
After evaporation, beautiful copper(II) chloride crystals should be in the container. The rest of the copper carbonate should dissolve and the solution should be very dark green. Add hydrochloric acid to it until most of it is dissolved and put it out to evaporate. This precipitate is mainly basic copper carbonate. You may reuse the solution for more copper electrolysis experiments. Eventually, the wire will become so encrusted with black copper(II) oxide that the electrolysis will stop.
Scrape the wires periodically to remove loose precipitate. A blue precipitate of copper compounds begins to form at the anode.
Oxygen may be released as bubbles at the anode. The hydrogen is seen as bubbles at the cathode. Hydrogen and copper(II) hydroxide and copper(II) carbonate are produced. If the resulting blue solution is not clear, it means that there is not enough hydrochloric acid present. If it changes color (gets more bluish), add more peroxide until it stops changing color. Add a little more hydrogen peroxide if a dark green coloration is observed after dissolution is completed. However, if not enough hydrogen peroxide is used, the copper reacts with the acidic copper(II) chloride solution to generate a dark green mixed copper(I)/copper(II) complex, which can cause problems as the salt dries, including the formation of an insoluble oxychloride or a monovalent chloride. After trying this method, it works wonderfully. As this experiment is very cheap, you can reproduce it with different levels of hydrogen peroxide and hydrochloric acid to find the ideal mixture. If you use 3% hydrogen peroxide, you may get next to nothing. A green solution of copper(II) chloride is produced.
Do not eat the crystals or drink the solution. Because sodium imparts an especially intense color to a flame, flashes of the sodium may be observed in nearly all solutions tested.Warning: Copper(II) chloride is toxic. It should be noted that sodium is present as an impurity in many if not most metal salts. A homemade atomizer was used to form a fine spray of the solution, which was sprayed directly into the burner flame. In these video sequences selected compounds, mostly metal salts, show the flame color in a Meeker burner flame. Some metal salts give off light outside of the visible region of the electromagnetic spectrum. Several metal salts give off a characteristic color visible to the human eye as is demonstrated by the alkali metals and a few other elements, but a fair number of metal salts give off light that may be observed, but is not sufficiently different in color to be differentiated from other metal salts. Upon returning to the ground state, they give off light (a line spectrum) characteristic of that metal. Metal ions combine with electrons in the flame and the metal atoms are raised to excited states because of the high flame temperature. Metal salts introduced into a flame give off light characteristic of the metal. These movies are 3 to 5 seconds in length. Aluminum chloride or magnesium chloride can be used to demonstrate that chlorine imparts no color to the flame. Except for boric acid, all compounds are chlorides. The flame colors are demonstrated close up. Aqueous solutions of various compounds are sprayed into a Meeker burner flame from an atomizer.