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

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The key difference between standard electrode potential and standard reduction potential lies in their definitions and applications:

  1. Standard Electrode Potential: This is a measure of the reducing power of any element or compound. It refers to the potential difference between the electrode and the electrolyte at equilibrium, when molar concentrations of all species involved in the half-cell are unity. The potential can be either positive or negative, depending on whether the species is more likely to be oxidized or reduced.
  2. Standard Reduction Potential: This is a measure of the tendency of a chemical species to be reduced. It is determined by measuring the potential difference between the cathode and anode under standard conditions and considers the reduction half-reaction as the reference. The standard reduction potential is always a positive value.

Standard electrode potentials can refer to either oxidation or reduction, while standard reduction potential mainly refers to the reduction half-reaction. Both potentials are measured under standard conditions, such as 298 K, 1 atm, and with 1 M solutions. To compare the relative reduction tendencies of different species, standard reduction potentials are often used, while standard electrode potentials help determine the overall cell potential.

Comparative Table: Standard Electrode Potential vs Standard Reduction Potential

The difference between standard electrode potential and standard reduction potential lies in their definitions and applications. Here is a comparison table highlighting the key differences:

Property Standard Electrode Potential Standard Reduction Potential
Definition The standard electrode potential is the electrical potential difference between the cathode and anode in an electrochemical cell under standard conditions. The standard reduction potential is the tendency for a chemical species to be reduced, measured in volts at standard conditions.
Application Standard electrode potentials are used to calculate the standard cell potential (E^o_cell) for an overall redox reaction. Standard reduction potentials are used to determine the standard cell potential by combining the standard reduction potential at the cathode and the standard oxidation potential at the anode.
Relationship The standard electrode potential is a combination of the standard reduction potential and the standard oxidation potential. The standard reduction potential is only one half of the overall standard electrode potential equation.

In summary, standard electrode potential refers to the overall potential difference between the cathode and anode in an electrochemical cell, while standard reduction potential measures the tendency of a species to undergo reduction. Standard reduction potentials can be combined with standard oxidation potentials to calculate the standard cell potential for an overall redox reaction.