Write equations to represent the following observations.

(a) A quantity of CuCl₂(s) is dissolved in concentrated HCl(aq) and produces a yellow solution. The solution is diluted to twice its volume with water and assumes a green color. On dilution to ten times its original volume, the solution becomes pale blue.

(b) When chromium metal is dissolved in HCl(aq), a blue solution is produced that quickly turns green. Later the green solution becomes blue-green and then violet.