Page 68 - MODERN ELECTROCHEMISTRY

ELECTROCHEMISTRY 13

Fig. 1.7. Physical chemistry and electrochemistry.
a view is implied in Fig. 1.8, where space limits the number of disciplines mentioned
that are associated with the study of electrified interfaces.
Apart from the large number of areas of knowledge associated with modern
electrochemistry, there are many areas to which it contributes or in which it plays an
essential role. Thus, much surface chemistry under real conditions involves moisture;
hence the electrified interfaces for which electrochemical concepts are relevant are as
wide in application as practical surface chemistry itself. This, together with the fact
that the subject embraces interactions between electric currents and materials (i.e.,
between two large areas of physics and chemistry), implies a widespread character for
the phenomena subject to electrochemical considerations (Fig. 1.8).

1.5.2. Some Examples of the Involvement of Electrochemistry in
Other Sciences

1.5.2.1. Chemistry. There are many parts of mainline chemistry that
originated in electrochemistry. The third law of thermodynamics grew out of
observations on the temperature variations of the potential of electrochemical reactions
occurring in cells. The concepts of pH and dissociation constant were formerly studied
as part of the electrochemistry of solutions. Ionic reaction kinetics in solution is
expressed in terms of the electrochemical theory developed to explain the “activity”
of ions in solution. Electrolysis, metal deposition, syntheses at electrodes, plus half of
the modern methods of analysis in solution depend on electrochemical phenomena.
Many biomolecules in living systems exist in the colloidal state, and the stability of
colloids is dependent on the electrochemistry at their contact with the surrounding
solution.

1.5.2.2. Metallurgy. The extraction of metals from their compounds
dissolved in molten salts, the separation of metals from mixtures in solution, and the