Among the listed reference electrodes, which has the highest standard potential?

Among the listed reference electrodes, which has the highest standard potential?

• A. The Standard Hydrogen Electrode (0 V)
• B. The Silver-Silver Chloride Electrode (0.197 V)
• C. The Saturated Calomel Electrode (0.242 V)
• D. A theoretical electrode with 0.300 V

Answer: (C)

In these reference electrodes, the standard potential is how strongly the electrode tends to be reduced relative to the standard hydrogen electrode, which is defined as zero volts. Among common references, the silver–silver chloride electrode sits above zero by a small amount, while the saturated calomel electrode sits higher still. A theoretical electrode with an even larger potential isn’t a real, widely used reference electrode, so it isn’t considered in practice. Therefore, among real reference electrodes, the saturated calomel electrode has the highest standard potential.

In these reference electrodes, the standard potential is how strongly the electrode tends to be reduced relative to the standard hydrogen electrode, which is defined as zero volts. Among common references, the silver–silver chloride electrode sits above zero by a small amount, while the saturated calomel electrode sits higher still. A theoretical electrode with an even larger potential isn’t a real, widely used reference electrode, so it isn’t considered in practice. Therefore, among real reference electrodes, the saturated calomel electrode has the highest standard potential.