Sign and Graphical Conventions

All cells are considered as the combination of two half-cells, with each of the latter represented by a half-reaction written as a reduction  

By use of an electromotive series (E° values) for standard half-reactions written as reductions (see Chapter 2) the potential of each half-cell can be calculated by means of the Nemst equation  

On this basis the half-cell with the more positive value will be the positive electrode (and the other the negative electrode) the algebraic difference of the two half-cell potentials equals the cell potential. 

An increasing number of chemists use electrochemistry as a characterization technique in a fashion analogous to their use of infrared, ultraviolet (UV)-visible, NMR, and electron spin resonance (ESR) spectroscopy. One of the main purposes of this book is to encourage this trend, and to provide practical 

As the later chapters indicate, a given question concerning a chemical system usually can be answered by any one of several electrochemical techniques. However, experience has demonstrated that there is a most convenient or reliable method for a specific kind of data. For example, polarography with a static or dropping-mercury electrode remains the most reliable electrochemical method for the quantitative determination of trace-metal ion concentrations. This is true for two reasons (1) the reproducibility of the dropping-mercury electrode is unsurpassed and (2) the reference literature for analysis by polarography surpasses that for any other electrochemical method by at least an order of magnitude. 

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