The Nernst Equation enables the determination of cell potential under non-standard conditions. It relates the measured cell potential to the reaction quotient and allows the accurate determination of equilibrium constants (including solubility constants).
The Nernst equation defines the relationship between cell potential to standard potential and to the activities of the electrically active (electroactive) species. It relates the effective concentrations (activities) of the components of a cell reaction to the standard cell potential.
Note that this is precisely the equation that we would obtain by writing out the Nernst equation corresponding to the chemical equation Ag++e−→Ag0. The standard electrode potentials are EPt∣Q,H2Q,H+=+0.699 v and EPt∣Fe3+,Fe2+=+0.783 v.
Since the temperature is equal to 25oC, the Nernst equation can be written as follows; Ecell = E0cell – (0.0592/n) log10Q. Here, two moles of electrons are transferred in the reaction. Therefore, n = 2. The reaction quotient (Q) is given by [Cd2+]/[Pb2+] = (0.02M)/(0.2M) = 0.1.
Importance of Nernst Equation The Nernst Equation allows for cell potential determination under non – standard conditions. It relates the measured cell potential to the quotient of the reaction and allows the exact determination of constants of equilibrium (including constants of solubility).
The Nernst equation is an important relation which is used to determine reaction equilibrium constants and concentration potentials as well as to calculate the minimum energy required in electrodialysis as will be shown later.
The Nernst equation is used to calculate the cell potential of an electrochemical cell at any given temperature, pressure, and reactant concentration. … Corrosion is an electrochemical process as it involves redox reactions between the metal and certain atmospheric agents.
The Nernst Equation enables the determination of cell potential under non-standard conditions. It relates the measured cell potential to the reaction quotient and allows the accurate determination of equilibrium constants (including solubility constants).
n = Number of moles of electrons used in reaction, F = Faraday = 96500 C/mol e- , [Products] = Concentration of products, [Reactants] = Concentration of reactants, T = temperature in K and.