Electrode Potential

Definition

Electrode potential is the potential difference that arises between an electrode and the solution in which it is immersed. It is a measure of the tendency of an electrode to lose or gain electrons, and it is a crucial concept in electrochemistry and the understanding of electrochemical cells.

5 Must Know Facts For Your Next Test

1. Electrode potential is measured relative to a reference electrode, typically the standard hydrogen electrode, which has a defined potential of 0 V.
2. The magnitude and sign of the electrode potential indicate the tendency of the electrode to undergo oxidation or reduction, with more positive potentials indicating a greater tendency for reduction.
3. Electrode potentials can be used to determine the direction of spontaneous electrochemical reactions and the voltage generated in an electrochemical cell.
4. The Nernst equation relates the electrode potential to the concentrations of the species involved in the half-reaction at the electrode.
5. Electrode potentials are influenced by factors such as temperature, pressure, and the presence of complexing agents in the solution.

Review Questions

• Explain the concept of electrode potential and how it is measured relative to a reference electrode.
  • Electrode potential is the potential difference that arises between an electrode and the solution in which it is immersed. It is a measure of the tendency of an electrode to lose or gain electrons. Electrode potentials are measured relative to a reference electrode, typically the standard hydrogen electrode, which has a defined potential of 0 V. The magnitude and sign of the electrode potential indicate the tendency of the electrode to undergo oxidation or reduction, with more positive potentials indicating a greater tendency for reduction.
• Describe how the Nernst equation is used to relate the electrode potential to the concentrations of the species involved in the half-reaction at the electrode.
  • The Nernst equation is used to relate the electrode potential to the concentrations of the species involved in the half-reaction at the electrode. The equation takes into account the standard electrode potential, the activities of the oxidized and reduced species, the number of electrons transferred in the half-reaction, and the temperature. By using the Nernst equation, it is possible to calculate the electrode potential under non-standard conditions and predict the direction of spontaneous electrochemical reactions.
• Analyze how factors such as temperature, pressure, and the presence of complexing agents in the solution can influence the electrode potential.
  • Electrode potentials can be influenced by various factors, including temperature, pressure, and the presence of complexing agents in the solution. An increase in temperature, for example, can affect the activities of the species involved in the half-reaction, leading to a change in the electrode potential. Similarly, changes in pressure can influence the electrode potential, particularly for reactions involving gases. The presence of complexing agents in the solution can also affect the electrode potential by altering the activities of the species involved in the half-reaction. Understanding how these factors can influence electrode potential is crucial for accurately predicting and analyzing electrochemical processes.

Related terms

Standard Electrode Potential:

The electrode potential of an electrode measured under standard conditions, where the activity of the ions in the solution is 1 M, the temperature is 25°C, and the pressure is 1 atm.

Reduction Potential:

The potential of an electrode when it is involved in a reduction half-reaction, where a species gains electrons and is reduced.

Oxidation Potential:

The potential of an electrode when it is involved in an oxidation half-reaction, where a species loses electrons and is oxidized.