Table of Contents
What is Electrode Potential?
The electrode potential is the potential difference between two electrodes in an electrolytic cell. It is determined by the nature of the electrode and the electrolyte. Therefore electrode potential can be used to predict the voltage of an electrolytic cell.
What is Standard Electrode Potential?
Standard electrode potential (E) is the voltage between the standard hydrogen electrode and a given electrode in a galvanic cell. The standard hydrogen electrode assigned a potential of 0 volts. The potential of a given electrode measured with respect to the standard hydrogen electrode. Therefore the standard electrode potential is a measure of the potential of a redox reaction.
Calculating Standard Reduction Potential for Zinc Electrode
Standard reduction potential calculated by subtracting the emf of the cell from the emf of the reference cell. However the reference cell is a cell with a standard electrode potential of zero.
The standard reduction potential for zinc is -0.76 V.
Electrochemical Series
In electrochemistry, the electrochemical series (sometimes called the “electrode series”) is a ranking of chemical elements according to their reduction potential. The reduction potential is a measure of the tendency of a chemical species to lose electrons. In other words, it is a measure of the ability of a chemical species to act as an oxidizing agent.
The electrochemical series is based on the half-cell reactions that occur in a battery. In a battery, one half-cell consists of a conductor (such as a metal) that immersed in a solution of ions. The other half-cell consists of a species that is capable of reducing the ions in the first half-cell. The reduction potential is a measure of the tendency of the species in the second half-cell to reduce the ions in the first half-cell.
The electrochemical series can be used to predict the order of reactivity of metals. The most reactive metal is at the top of the series and the least reactive metal is at the bottom. The reactivity of metals can also affected by the presence of other elements. For example, the reactivity of a metal can decreased by the presence of a noble gas.
Uses of Standard Electrode Potentials
- Standard electrode potentials used in a variety of ways. However one way is to calculate the equilibrium constant for a chemical reaction.
- The equilibrium constant is a measure of how much a reaction favors the products over the reactants.
- Another way to use standard electrode potentials is to calculate the voltage of a battery.
Limitation of Standard Electrode Potentials
There are several limitations to using standard electrode potentials to predict redox reactions.
- The standard electrode potentials are only valid for aqueous solutions.
- electrode potentials do not take into account the reactants’ concentrations.
- The standard electrode potentials do not take into account the solubility of the reactants.
- also electrode potentials are not temperature dependent.
