GENERAL KNOWLEDGE

DEFINE STANDARD ELECTRODE POTENTIAL

Standard electrode potential, also known as standard reduction potential, is a measure of the tendency of an electrode to gain or lose electrons when it is connected to a reference electrode. It is defined as the potential difference between the electrode and the standard hydrogen electrode (SHE) under standard conditions (1 atm pressure, 298 K temperature, and 1 M concentration).

The value of standard electrode potential depends on several factors:

  1. Nature of the electrode material: Different materials have different affinities for gaining or losing electrons. For example, metals with a higher ionization energy tend to have more positive standard electrode potentials.
  2. Concentration of ions in solution: The concentration of ions in solution affects the distribution of charges at the interface between the electrode and the solution. This can lead to changes in the standard electrode potential.
  3. Temperature: The temperature affects the kinetic energy of the particles involved in the redox reaction. As a result, it influences the rate at which electrons are transferred between the electrode and the solution, thereby affecting the standard electrode potential.
  4. Pressure: In most cases, pressure does not significantly affect the standard electrode potential. However, in some cases where gases are involved in redox reactions, changes in pressure can influence the partial pressure of gases and alter the equilibrium position.

The values of standard electrode potential have several important uses:

  1. Predicting spontaneous redox reactions: By comparing the standard electrode potentials of two half-cells, it is possible to determine which half-reaction will occur spontaneously and which direction electrons will flow.
  2. Designing electrochemical cells: The values of standard electrode potentials help in selecting suitable electrodes for constructing electrochemical cells. Electrodes with larger positive standard potentials are more likely to act as cathodes (gain electrons), while those with smaller positive potentials are more likely to act as anodes (lose electrons).
  3. Calculating cell potentials: The difference between the standard electrode potentials of the two half-cells in an electrochemical cell determines the overall cell potential. This information is crucial for understanding the behavior and efficiency of electrochemical systems.
  4. Determining the feasibility of electrolysis: The standard electrode potentials can be used to determine if a given electrolysis process is feasible or not. If the applied potential is more positive than the standard electrode potential, the electrolysis reaction will occur.
  5. Understanding corrosion and oxidation-reduction reactions: Standard electrode potentials help in understanding the corrosion process and predicting the reactivity of different metals. The more negative the standard electrode potential of a metal, the more likely it is to corrode.
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