A solution of KI is added dropwise to a pale blue solution of Cu(NO₃)₂. The solution changes to a brown color, and a precipitate of CuI forms. In contrast, no change is observed if solutions of KCl and KBr are added to aqueous Cu(NO₃)₂. Consult the table of standard reduction potentials to explain the dissimilar results seen with the different halides. Write an equation for the reaction that occurs when solutions of KI and Cu(NO₃)₂ are mixed.