What is the standard emf for the cell formed by Cu2+/Cu as the anode and Ag+/Ag as the cathode?

• A. 0.46 V
• B. 1.14 V
• C. -0.46 V
• D. 0.08 V

Answer: (A)

The standard emf of a cell is the difference between the reduction potentials of the cathode and the anode: E°cell = E°cathode − E°anode. The Ag+/Ag couple has a reduction potential of +0.80 V, while the Cu2+/Cu couple has a reduction potential of +0.34 V. Since copper is the anode (oxidation) and silver is the cathode (reduction), E°cell = 0.80 V − 0.34 V = +0.46 V. This positive value means the reaction is spontaneous under standard conditions, with the overall reaction: Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s).