The key difference between standard electrode potential and standard reduction potential is that standard electrode potential is the tendency of an electrode to lose or gain electrons, whereas standard reduction potential is the tendency of a chemical species to be reduced.
The terms standard electrode potential and standard reduction potential are usually used interchangeably because it is difficult to measure the accurate potential of an electrode alone rather than measuring the overall potential. However, standard electrode potential can refer to either oxidation or reduction, while standard reduction potential mainly refers to reduction half-reaction.
CONTENTS
1. Overview and Key Difference
2. What is Standard Electrode Potential
3. What is Standard Reduction Potential
4. Standard Electrode Potential vs Standard Reduction Potential in Tabular Form
5. Summary – Standard Electrode Potential vs Standard Reduction Potential
What is Standard Electrode Potential?
Standard electrode potential can be described as the measurement of the potential for an equilibrium. In other words, it is the potential difference between the electrode and the electrolyte named as the potential of the electrode. It measures the reducing power of any element or compound. According to the IUPAC gold book, the standard electrode potential is the value of the standard emf (electromotive force) of a cell where molecular hydrogen under standard pressure is oxidized to solvated protons at the left-handed electrode.
Usually, the basis of an electrochemical cell is a redox reaction that consists of two half-reactions. These are the oxidation at the anode and reduction at the cathode. Therefore, electricity forms due to the difference in electric potential between the individual potentials of the two metal electrodes with regard to the electrolyte.
We can simply measure the overall potential of a cell. But the accurate measurement of the electrode potential in isolation is very difficult. This phenomenon varies with temperature, concentration, and pressure. The oxidation potential of a half-reaction can be described as the negative of the reduction potential in a redox reaction. Therefore, this potential is sufficient for calculating either one of the potentials. This leads to the use of the terms standard electrode potential and standard reduction potential to be used interchangeably.
What is Standard Reduction Potential?
Standard reduction potential can be described as the potential in volts generated by the reduction half-reaction of redox reactions in comparison with the standard hydrogen electrode at 25 degrees Celsius, 1 atom pressure, and 1M concentration. In other words, we can define this term relative to a standard hydrogen electrode. This hydrogen electrode is assigned as the 0.00 V potential standard. The denotation of standard reduction potential can be done using “E0”.
Generally, the standard reduction potential is calculated for the half-reaction that is occurring at the cathode as the reduction half-reaction. The standard reduction potential is very useful in chemistry. Sometimes, the term standard electrode potential is also used interchangeably with this term. The measurement of the standard reduction is done using volts (V). The standard reduction potential gives us information about how likely an element or ion is to get reduced by gaining electrons.
What is the Difference Between Standard Electrode Potential and Standard Reduction Potential?
The key difference between standard electrode potential and standard reduction potential is that the standard electrode potential is the tendency of an electrode to lose or gain electrons, whereas the standard reduction potential is the tendency of a given chemical species to be reduced. However, these two terms are used interchangeably because the term standard electrode potential can be used for both the reduction and oxidation half-reactions.
The below infographic presents the differences between standard electrode potential and standard reduction potential in tabular form for side-by-side comparison.
Summary – Standard Electrode Potential vs Standard Reduction Potential
Standard electrode potential is the measurement of the potential for equilibrium, while standard reduction potential is the potential in volts generated by the reduction half-reaction of redox reactions. The key difference between standard electrode potential and standard reduction potential is that the standard electrode potential is the tendency of an electrode to lose or gain electrons, whereas the standard reduction potential is the tendency of a given chemical species to be reduced.
Reference:
1. Helmenstine, Anne Marie. “Standard Reduction Potential Definition.” ThoughtCo, Aug. 28, 2020.
Image Courtesy:
1. “EN & SEP of nonmetallic elementsF” By Sandbh (original April 2018 version); YBG (June 2018 versions) – Own work (CC BY-SA 4.0) via Commons Wikimedia