Standard Electrode Potential

Definition

The standard electrode potential is a measure of the tendency of an electrode to gain or lose electrons when it is in its standard state, which is defined as the potential of the electrode when it is in its standard state and the reaction is at standard conditions (25°C, 1 atm pressure, and 1 M concentration of all solutes). It is a fundamental concept in electrochemistry and is used to predict the direction and spontaneity of redox reactions.

5 Must Know Facts For Your Next Test

1. The standard electrode potential is measured relative to the standard hydrogen electrode, which is assigned a potential of 0 V.
2. Positive standard electrode potentials indicate a tendency to be reduced, while negative standard electrode potentials indicate a tendency to be oxidized.
3. The standard electrode potential can be used to predict the direction and spontaneity of redox reactions, with the reaction occurring spontaneously in the direction that increases the overall cell potential.
4. The standard electrode potential is affected by temperature, pressure, and the concentration of the reactants and products, and can be adjusted to non-standard conditions using the Nernst equation.
5. The standard electrode potential is a key factor in determining the electrochemical series, which is used to predict the relative reactivity of elements and the spontaneity of redox reactions.

Review Questions

• Explain how the standard electrode potential is defined and how it is used to predict the direction of redox reactions.
  • The standard electrode potential is a measure of the tendency of an electrode to gain or lose electrons when it is in its standard state, which is defined as the potential of the electrode when it is in its standard state and the reaction is at standard conditions (25°C, 1 atm pressure, and 1 M concentration of all solutes). Positive standard electrode potentials indicate a tendency to be reduced, while negative standard electrode potentials indicate a tendency to be oxidized. The standard electrode potential can be used to predict the direction and spontaneity of redox reactions, with the reaction occurring spontaneously in the direction that increases the overall cell potential.
• Describe how the standard electrode potential is affected by changes in temperature, pressure, and the concentration of reactants and products, and explain how the Nernst equation can be used to adjust the standard electrode potential to non-standard conditions.
  • The standard electrode potential is affected by temperature, pressure, and the concentration of the reactants and products. As the temperature increases, the standard electrode potential generally becomes more negative, indicating a decreased tendency for reduction. Increased pressure can also affect the standard electrode potential, depending on the specific reaction. Additionally, the concentration of the reactants and products can influence the standard electrode potential, with higher concentrations generally resulting in more positive potentials. The Nernst equation can be used to adjust the standard electrode potential to non-standard conditions by taking into account the effects of temperature, pressure, and concentration on the electrode potential.
• Discuss the relationship between the standard electrode potential and the electrochemical series, and explain how the electrochemical series can be used to predict the relative reactivity of elements and the spontaneity of redox reactions.
  • The standard electrode potential is a key factor in determining the electrochemical series, which is a list of elements arranged in order of decreasing standard electrode potential. This series reflects the relative tendency of the elements to lose or gain electrons, and can be used to predict the spontaneity of redox reactions. Elements with more positive standard electrode potentials have a greater tendency to be reduced, and are therefore more reactive, while elements with more negative standard electrode potentials have a greater tendency to be oxidized and are less reactive. By comparing the standard electrode potentials of the reactants and products in a redox reaction, it is possible to predict the direction and spontaneity of the reaction, with the reaction occurring spontaneously in the direction that increases the overall cell potential.

Related terms

Reduction Potential: The reduction potential of an electrode is a measure of the tendency of the electrode to be reduced, or to gain electrons, when it is in its standard state.

Oxidation Potential: The oxidation potential of an electrode is a measure of the tendency of the electrode to be oxidized, or to lose electrons, when it is in its standard state.

Electrochemical Series: The electrochemical series, also known as the activity series or reactivity series, is a list of elements arranged in order of decreasing standard electrode potential, which reflects their relative tendency to lose or gain electrons.