Aqueous solution, ion

Usnally, only very dilute solutions can be considered ideal. In most aqueous solutions, ions are stabilized because they are solvated by water molecules. As the ionic strength is increased, ions interact with each other. Thus, when calculating the chemical potential of species i, a term that takes into account the deviation from ideal conditions is added. This term is called an excess term and can be either positive or negative. The term usually is written as 7 riny., where y. is the activity coefficient of component i. The complete expression for the chemical potential of species i then becomes... 

IONIC SPECIATION. Ions interact continually in aqueous solution. Ions are complexed with water molecules. Even when we say that a certain ion is uncomplexed, the fact is that the ion is still complexed, in this case with water molecules. Association constants (also known in the literature as stability or formation constants) allow one to quantitate the extent to which an ion is complexed with any particular substance in solution. They also allow comparisons of the relative affinity of different complex-ing agents for a particular chemical substance. Speciation is a chain of linked binding functions (see Fig. 3). Such diagrams show the relative concentrations of the various complexes in solution, and the reversible equilibria existing between these pools are shown by the arrows. 

These examples are sufficient to form the basis of the discussion of the nature of cations and anions in aqueous solutions. In aqueous solution, ions are stabilized by their interaction with the solvent they become h>drated and this slate is indicated in equations by the (a< ) symbolism. This is a broad generalization and is amplified by further discussions in the next sections and in the remainder of the book. 

Acids and Bases Forms of Ions in Aqueous Solution Ion Hydrolysis Compound Solubility... 

Many potentiometric studies have been carried out to obtain information about the compositions and formation constants of metal complexes in non-aqueous solutions. Ion-selective electrodes and metal (or metal amalgam) electrodes are used as indicator electrodes. 

Keywords aqueous solution, ions, coupling, Darcy coefficient, free energy, stress, strain,... 

A net ionic equation describes the actual reaction between ions of compounds in aqueous solution. Ions that do not change at all during the reaction are omitted from... 

In general, partition of components from a solution at a solid surface provides the principle that is most often exploited (adsorption is used only very rarely), but for amino acids and peptides, which can exist in charged forms in aqueous solutions, ion-exchange and electrophoresis separation are also available. Separation on the basis of molecular size is also used. 

Electrocatalysis in metallic corrosion may be classified into two groups Adsorption-induced catalyses and solid precipitate catalyses on the metal surface. In general, the bare surface of metals is soft acid in the Lewis acid-base concept and tends to adsorb ions and molecules of soft base forming the covalent binding between the metal surface and the adsorbates. The Lewis acidity of the metal surface however may turn gradually to be hard as the electrode potential is made positive, and the bare metal surface will then adsorb species of hard base such as water molecules and hydroxide ions in aqueous solution. Ions and molecules thus adsorbed on the metal surface catalyze or inhibit the corrosion processes. Solid precipitates, on the other hand, are produced by the combination of hydrated cations of hard acid and anions of hard base forming the ionic bonding between the cations and the anions on the metal surface. 

Natural surface ectivity In assoc ialion with surface-active agents Foam fractionation for example, dete[gents from aqueous solutions Ion flotation, molecular flotation, adsorbing colloid flotation for example, Sr1 +, PtiJ +, Hg2+, cyanides Fnam flotation for example, microurganisms, proteins Microflotation, colloid flotation, ultraflotation for example, particulates in wastewater, clay, microoiganisms Froth flotation of noapolar minerals for example, sulfur Froth flotation For example minerals such as silica Precipitate flotation (1st and 2nd kind) Tor example, ferric hydroxide... 

GOL/NUT] Goldberg, R. N., Nuttall, R. L., Staples, B. R., Evaluated activity and osmotic coefficients for aqueous solutions Ion chloride and the bi-univalent compounds of nickel and cobalt, J. Phys. Chem. Ref. Data, 8, (1979), 923-1003. Cited on pages 156, 158, 197, 387. 

In the second half of the sixties, a new paradigm was formed, which says that collecting agents form complex structures on individual areas of 1/s interfaces. In this aspect, the selectivity of the surface ion-aqueous solution ion interaction was based on the ideas of the classical analytical chemistry of solutions. 

In very dilute aqueous solutions, ions behave independently of one another and it is valid to assume that activity coefficients of ions have values of unity. However, g Jlhe,concep4j tio5>.of. i xi creases, electrostatic interactions between the ions also increase and the activity Q is ec I) . .. 

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