The document discusses the concept of absolute electrode potential and its thermodynamic basis. It clarifies common misunderstandings about the physical meaning of absolute electrode potential, emphasizing that it is not simply the electric potential difference between a metal and a solution, but rather a measure of the energy levels of species in the two phases. The correct expression for absolute electrode potential is derived through a thermodynamic analysis of the components of the electromotive force (emf) of an electrochemical cell. It is shown that three reference levels can be chosen to measure an absolute value of the electrode potential, but only one of these is suitable for meaningful comparisons between electrochemical and physical parameters. The document recommends a critically evaluated value for the absolute potential of the standard hydrogen electrode in water and in a few other protic solvents. It concludes that the absolute potential of the standard hydrogen electrode in water is (4.44 ± 0.02) V at 298.15 K. The document also discusses the importance of using a correct scale for absolute electrode potentials, particularly in the context of comparing electrochemical and physical parameters. It highlights the need for a universal reference system and the challenges in determining absolute potentials experimentally. The document also addresses the differences between various reference systems and the implications for the measurement of absolute electrode potentials in different solvents.The document discusses the concept of absolute electrode potential and its thermodynamic basis. It clarifies common misunderstandings about the physical meaning of absolute electrode potential, emphasizing that it is not simply the electric potential difference between a metal and a solution, but rather a measure of the energy levels of species in the two phases. The correct expression for absolute electrode potential is derived through a thermodynamic analysis of the components of the electromotive force (emf) of an electrochemical cell. It is shown that three reference levels can be chosen to measure an absolute value of the electrode potential, but only one of these is suitable for meaningful comparisons between electrochemical and physical parameters. The document recommends a critically evaluated value for the absolute potential of the standard hydrogen electrode in water and in a few other protic solvents. It concludes that the absolute potential of the standard hydrogen electrode in water is (4.44 ± 0.02) V at 298.15 K. The document also discusses the importance of using a correct scale for absolute electrode potentials, particularly in the context of comparing electrochemical and physical parameters. It highlights the need for a universal reference system and the challenges in determining absolute potentials experimentally. The document also addresses the differences between various reference systems and the implications for the measurement of absolute electrode potentials in different solvents.