What is the Difference Between Single Electrode Potential and Standard Electrode Potential?

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The key difference between single electrode potential and standard electrode potential lies in the conditions and the reference used for the measurement:

  1. Single Electrode Potential: This is the electric potential of one electrode in an electrochemical cell containing two electrodes, known as half cells. It is not directly measurable, as only the difference between the potentials of two electrodes can be measured.
  2. Standard Electrode Potential: This is the potential of an electrode at standard conditions, which include a temperature of 25°C, a pressure of 1 atmosphere, and a 1M molar concentration of ions in the electrolyte. The standard electrode potential is measured against the standard hydrogen electrode (SHE) potential, which is arbitrarily assigned a value of 0 V. All tabulated values of standard electrode potentials are listed as standard reduction potentials.

In summary:

  • Single electrode potential is the electric potential of one electrode in an electrochemical cell, but it is not directly measurable.
  • Standard electrode potential is the potential of an electrode at standard conditions, measured against the standard hydrogen electrode potential.

Comparative Table: Single Electrode Potential vs Standard Electrode Potential

The difference between single electrode potential and standard electrode potential lies in the conditions and the reference used for measurement. Here is a comparison table highlighting the key differences:

Parameter Single Electrode Potential Standard Electrode Potential
Definition The electric potential of one electrode in an electrochemical cell. The potential of an electrode at 1-atmosphere pressure, 25°C temperature, and 1M molar concentration of ions in the electrolyte.
Measurement Cannot be measured directly; only the difference between the potentials of two electrodes can be measured. Measured against the standard hydrogen electrode potential, which is assigned a value of 0 V.
Conditions Depends on factors such as concentration of ions in the solution, tendency to form ions, and temperature. Standard conditions are defined as 1 atm pressure, 25°C temperature, and 1 M molar concentration of ions in the electrolyte.
Reference Potential is relative to the other electrode in the cell. Potential is measured against the standard hydrogen electrode.

In summary, single electrode potential is the electric potential of one electrode in an electrochemical cell, but it cannot be measured directly and varies with factors such as concentration, temperature, and pressure. On the other hand, standard electrode potential is the potential of an electrode under standard conditions, measured against the standard hydrogen electrode potential.