1. The problem statement, all variables and given/known data Cu2+ ions react with Fe2+ ions according to the following reaction. Cu2+ + 2Fe2+ --> Cu + 2Fe3+ At equilibrium, the concentration of Cu2+ ions is not changed by the addition of A) Cu2++ B) Fe2+ C) Cu D) Fe3+. 2. Relevant equations 3. The attempt at a solution I chose A through elimination. B won't work because the equilibrium will shift to the right if Fe2+ is added. C and D won't work because the equilibrium will shift to the right. Therefore A seems the most correct. However, if Cu2+ is added, then the equilibrium will also shift to the right. This means that it shifts to the right until the Cu2+ concentration is back to what it was before which seems impossible. Could someone shed some light on this?