What is the standard cell potential E°cell for the galvanic cell Zn(s) | Zn2+ (1.0 M) // Cu2+ (1.0 M) | Cu(s)?

• A. 0.76 V
• B. 1.10 V
• C. 1.28 V
• D. 0.34 V

Answer: (B)

Standard cell potential comes from how strongly each species tends to gain or lose electrons, expressed as the difference between the cathode’s reduction potential and the anode’s reduction potential: E°cell = E°cathode − E°anode. Here the cathode is Cu2+/Cu with E° = +0.34 V, and the anode is Zn2+/Zn with E° = −0.76 V. So E°cell = 0.34 − (−0.76) = 1.10 V. The positive value means the reaction Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) is spontaneous under standard conditions, giving a standard cell potential of 1.10 V.