Conductimetry ionic conductivity

As described in Section 5.8, the conductivity of electrolyte solutions is a result of the transport of ions. Thus, conductimetry is the most straightforward method for studying the behavior of ions and electrolytes in solutions. The problems of electrolytic conductivity and ionic transport number in non-aqueous solutions have been dealt with in several books [1-7]. However, even now, our knowledge of ionic conductivity is increasing, especially in relation to the role of dynamical solvent properties. In this chapter, fundamental aspects of conductimetry in non-aqueous solutions are outlined. 

A number of methods have been used for determining Kg values cation selective electrodes, pH-metric methods, conductimetry, calorimetry, temperature-jump relaxation measurements, membrane conductance measurements, nuclear magnetic resonance, optical rotatory dispersion. The results listed in Tables 7—10 have been obtained by various methods and at different ionic strengths so they may not always be strictly comparable. However, the corrections are probably small and the experimental accuracy is generally the same or very similar within a certain ligand type. 

The impurity interacts with a substance participating in the process to be measured. An example is met when we determine the dissociation constant (pfQ of a weak acid HA by conductimetry. In the determination, we dissolve HA in the pure solvent and measure the conductivity of the solution containing dilute H+ and A formed by dissociation. If a basic impurity B is contained in the solution, it disturbs the measurement, producing ionic species by the reaction B+HA — BH++A . Because trace amounts of basic impurity are contained even in a purified solvent, conductimetric pK determination is practically impossible for HA with pfCa>7.5. 

Conductivity. Electrical conductivity measurements are appealingly simple and sensitive, and reflect the charge carrying ability (carrier population and mobility) of a test medium Interposed between two electrodes biased by DC or AC potentials. The key for chemical sensoring is to design some element of chemical selectivity Into the values of carrier population or mobility. Measurements in liquid ionic solutions (the classical method of conductimetry) have little intrinsic... 

Conductimetry (the measurement of conductivity) is a physical chemical measurement that provides information about the total ionic content of aqueous solutions. Using conductimetric techniques, electrolytic properties of ions such as diffusion, transport, mobility, and migration have been extensively studied and reported. Dissociation and dielectric constants of compounds have similarly been the subject of these physical chemistry studies in both aqueous and nonaqueous solutions. 

Conductivity This parameter helps to establish water quality and its temporal changes. Also, it allows dissolved solids to be quantified. This parameter is measured by conductimetry and is related to the total ionic concentration. 

---