Solutions Of Strong Electrolytes Research Articles

Wien effect in mixed strong electrolytes

A method of Fourier transformations and matrix representations is formulated for the computation of Wien effect in diluted solutions of mixed strong electrolytes. The method permits the extension of the computation to systems containing any number of species of ions of any valence type. Thus, for the first time Wien effect of mixed electrolytes is computed from the fundamental equations of ion–ion interactions. At very low field strengths, where Ohm’s law is obeyed, the integral representation of Onsager and Kim is reproduced. At extremely high field strengths, the relaxation effect and the electrophoretic effect are computed to the second order term. At intermediate field strengths, the equations for the computation of the relaxation effect and the electrophoresis by triple integrations are derived.

Rapidly converging activity expansions for representing the thermodynamic properties of fluid systems: gases, non-electrolyte solutions, weak and strong electrolyte solutions

For dilute gases and non-electrolyte solutions in the McMillan–Mayer standard state, an activity expansion due to Mayer has great advantages over the normal concentration expansion (virial equation) for strongly associating species. For weakly interacting systems, both approaches are suitable. The activity expansion eliminates the need to differentiate between strong “chemical” interactions and weak “physical” interactions since the same equation is used in each situation.The equation has been modified to represent electrolyte solutions in the McMillan–Mayer standard state by requiring that it be consistent with the Debye–Huckel and higher order limiting laws for strong electrolytes and that it be equivalent to a chemical association model for weak electrolytes. The result is a compact equation which contains no arbitrary ion-size parameters and which does not require the classification of an electrolyte as strong or weak. For 2:2 electrolytes, the equation gives a very good fit to the anomalous low concentration region.For practical thermodynamic calculations, similar equations for molal activity coefficients are proposed; good fits of the data are obtained.

各種強電解質水溶液中への水素ガスの溶解

A study on the dissolution behavior of hydrogen gas in aqueous solutions containing strong electrolytes was done to elucidate the dependence of both concentration and effective diameters of electrolyte-constituting ions upon the solubility, as well as the dissolution rate, of hydrogen gas. The main results obtained are as follows:(1) Dissolution rate of hydrogen gas, and its solubility as well, in the aqueous solutions of strong electrolytes decreases with the increase in both the concentration of electrolytes and the effective diameters of electrolyte-constituting ions.(2) Solubility of hydrogen gas in a binary H2 SO4-CuSO4 solution can be estimated as the sum of the solubilities of hydrogen gas in the respective solutions.(3) The value of hydrogen solubility in an aqueous solution containing strong electrolyte can be roughly estimated by taking the concentration of electrolyte and the effective diameter of constituting ions into considerations.(4) The rate of hydrogen reduction of silver from a silver nitrate solution at 50°C and 500 rpm was found to be controlled by the dissolution rate of hydrogen gas in the aqueous solution.

Ionic association in aqueous solutions of strong electrolytes

A more accurate calculation of relaxation effects obtained with the standard Debye-Huckel-Onsager model has been presented recently and is here applied to several aqueous 1:1 electrolytes. The variation of the standard deviation between calculated and observed equivalent conductivities withK A leads to an ill-defined minimum; but, where data over a wide concentration range are available, the minimum corresponds to values of the contact distancea which approximate to estimates from ionic dimensions. It is therefore proposed that, although preciseK A values from conductance cannot be determined, the most probable values are those associated with realistic estimates ofa. When data cover a limited concentration range, minimum standard deviations are often indeterminate or vary greatly for duplicate runs. It is shown that reasonable values ofK A can be obtained from such data if comparison is made at estimated values ofa.

Theory of a “two-dimensional electrolyte solution”

Let us assume that on a flat interface of two semi-infinite nonmetallic media, which we designate by indices 0 and 1, there occurs nonlocalized adsorption of ions of both signs from medium 0. Since the adsorbed ions are fairly strongly bonded to the interface, they are simultaneously capable of freely moving over the surface. Such a possibility leads to a correlation of the mutual arrangement of ions and, hence, to the appearance of an electric twodimensional (negative) pressure in addition to an ordinary osmotic pressure and the surface tension of a pure solvent. Further, we limit ourselves to considering such a system at an isoelectric point, in which both the bulk of the electrolyte and the interface are electrically neutral. Moreover, let us assume that the bulk concentration of ions is very small. To calculate the thermodynamic values of such a two-dimensional electrolyte solution, let us apply a method which is analogous to the three-dimensional theory of strong electrolyte solutions, i.e., the DebyeHiickel theory (see, for example, (1)). First, it will be necessary to calculate the Coulomb part of the internal energy of twodimensional solution :

Collective vibrational modes in strong electrolyte solutions at high concentrations

We report evidence for the existence of solute related collective vibrational modes in strong II-I electrolyte solutions at high concentrations both in H 2O and D 2O. The evidence was obtained by studying the polarized Raman spectra of solutions of CdCl 2 and NiCl 2 Checks were also performed by taking the Raman spectra of the relative hydrated salts. Our results are explained in terms of vibrational densities of states corresponding to collective vibrational modes in a solute connected middle range lattice.

Theory of concentrated solutions of strong electrolytes. Part 1.—Some thermodynamic quantities of a lattice-like network of ions surrounded by a dielectric gradient

Calculations have been carried out on a model of electrolyte solutions with the following features: (i) the ions of the strong binary electrolyte are distributed in a lattice-like arrangement, (ii) ions are immersed in an incompressible, structure-less, continuous dielectric but this medium has a dielectric gradient in the vicinity of ions due to the polarizing effect of their electric field, (iii) coulombic interaction is calculated with respect to an average dielectric “constant” depending on the interionic separation distance, and (iv) the dielectric gradient regions around the ions result in a repulsive force between ions due to the work required to remove solvent from the dielectric gradient region when lowering the interionic separation distance. Comparison of calculated and observed data for the average dielectric constant, mean ionic activity coefficients, and partial molar enthalpy contents of several 1–1 and 1–2 electrolytes shows fairly good agreement, in some cases in the entire concentration range, with no adjustable parameters involved.

Shock polarization of solutions of strong electrolytes

It is shown that the main cause of shock emf in shock compression of a metal-electrolyte-metal system is shock polarization of the electrolyte solution. The emf is linearly dependent on ion mass and is an additive function of the ion composition of the electrolyte solution. The relaxation time for the nonequilibrium processes produced by shock polarization of the metal-electrolyte boundary does not exceed 5·10−7 sec for single-time compression.

Thermodynamic properties of strong electrolyte solutions from correlation functions

General relations are presented to relate the fluctuation thermodynamic properties of multicomponent electrolyte solutions (concentration derivatives of the chemical potential, partial molar volume, and compressibility) to integrals of the total correlation function (Kirkwood-Buff solution theory) and of the nondivergent portion of the direct correlation function. Detailed expressions are given for the single-salt, single-solvent system. It appears that the direct correlation function expressions may be of more practical use in developing correlations for solution properties because, unlike the total correlation functions, terms exist which distinguish between cation and anion interactions with water and with other ions.

A Theory of Ion Association as a Complement of the Debye-Hückel Theory

Abstract The classical Debye-Hückel theory of strong electrolyte solutions was re-examined in order to explain ion association. Regarding a symmetrical electrolyte in very dilute solutions, a more precise expression was derived for excess chemical potential due to electrostatic ion-ion interactions. This expression has, in addition to the Debye-Hückel term, a supplementary term resulting from a more proper account of the energy of the interactions of ions existing near each other. If the concept of ion association is taken as a complement of the Debye-Hückel theory, the contribution to the chemical potential of the electrolyte from ion association should correspond to the supplementary term. The following equation was thus obtained for the ion-association constant: K=(8πNa^3/1000) \overset∞\undersetn=1∑b^2n+2/[(2n+2)! (2n-1)] This equation is in agreement with that derived by Ebeling on the basis of the cluster theory and has an asymptotic representation (at b→∞) in common with Bjerrum’s. For practical b values, the present equation has the merit that it gives moderate K values, decreasing monotonously with an increase in the a value, and eliminates the disadvantages of Fuoss’s result, giving a minimum K value at b=3, and of Bjerrum’s, giving K=0 at ≤2.

On the thermodynamics of concentrated strong electrolytes aqueous solutions the system NaNO3—NaCl—H2O

AbstractA simple analytical function is proposed for the calculation of molar excess Gibbs energy of binary solutions of strong electrolytes in water. Empirical parameters can be easily determined from experimental data reported in the literature.The treatment is extended to ternary solutions and to solid liquid equilibria using an empirical equation. Absence of solid solutions is assumed.The correlations are applied to the common ion ternary system NaNO3‐NaCl‐H2O in the temperature range from 0 to 100°C.Predictions of activity coefficients of the binary systems and saturation curves of the ternary system are in good agreement with experimental data.

ChemInform Abstract: ESTIMATION OF INDIVIDUAL IONIC ACTIVITY COEFFICIENTS FROM CONDUCTIVITY DATA ON STRONG ELECTROLYTES IN DILUTE AQUEOUS SOLUTIONS

AbstractDie einzelnen Ionenaktivitätskoeffizienten starker Elektrolyte in verdünnten wäßrigen Lösungen werden aus Ionenleitfähigkeitsdaten unter Anwendung der Debye‐ Hückel‐Onsager‐Theorie starker Elektrolytlösungen abgeleitet.

Estimation of Individual Ionic Activity Coefficients from Conductivity Data on Strong Electrolytes in Dilute Aqueous Solutions

Abstract The individual ionic activity coefficients of strong electrolytes in dilute aqueous solutions are derived from the ionic conductivity data, using the Debye-Hückel-Onsager theory of strong electrolyte solutions. The mean activity coefficients computed by the present method are in good agreement with the experimental values in most of the uni-univalent and some of the uni-multivalent electrolytes studied, which demonstrates the validity of the method in deriving the individual ionic activity coefficients. Comparisons are made of the values of individual activity coefficients of various ions in dilute aqueous solutions of strong electrolytes, as determined by different methods including measurements of potential differences across membranes at varying concentrations. The influence of the ion of opposite sign on the individual ionic activity coefficient has been observed.

Potential theory of strong electrolyte solutions using the Bogoliubov-Born-Green-Yvon integral equations

A potential analysis of strong electrolyte solutions is undertaken using the BBGY hierarchy of integral equations. An estimate for the fluctuation potential is found which implies damped oscillatory solutions of the Debye-Huckel potential for κa ⩾ 1·720 (κ = Debye-Huckel constant, a = ionic diameter). The relation to the work of Martynov is also given.

Reformulation of the nth order poisson equation in strong electrolyte solution theory using the kirkwood integral equations

Reformulation of the nth order poisson equation in strong electrolyte solution theory using the kirkwood integral equations

Reformulation of the nth order poisson equation in strong electrolyte solution theory using the kirkwood integral equations

A Poisson equation for the nth order mean potential has previously been derived in the case of the primitive model of an electrolyte solution using the Kirkwood integral equations. We generalise this analysis to the case of an arbitrary short range pair potential between the ions.

Higher-order closures and potential problems in diffuse double layer and strong electrolyte solution theory

An nth-order closure is proposed between the higher-order fluctuation potentials of the mean electrostatic potentials and the potentials of the mean force. At the zeroth level the closure gives the Gouy-Chapman theory, at the first level the Loeb extension of the Gouy-Chapman theory and the Debye-Hückel theory, and at the second level the Outhwaite extension of the Debye-Hückel theory together with the equivalent problem in the diffuse double layer. Using the primitive model for the electrolyte with a plane uniformly charged electrode producing the double layer, a statistical mechanical analysis is carried out to determine the relations between the higher-order potentials of the mean force and the mean potentials. For the nth-order closure this gives a system of n + 1 differential equations in the diffuse double layer or n differential equations in the electrolyte bulk satisfied by the higher-order fluctuation potentials.

Effect of salts on the rate of mass transfer across a plane interface between a gas and mechanically agitated aqueous solutions of inorganic electrolytes

The mass transfer coefficient of physical absorption by a free surface into agitated liquid was measured. Oxygen and helium were being absorbed into water and solutions of strong inorganic electrolytes. It has been found that the mass transfer coefficient decreases with increasing salt concentration. This has been attributed to the surface film properties of the electrolyte solutions. Correlations for single-component liquids, suggested in the literature, are short of yielding an adequate description of the changes in mass transfer coefficient values provoked by the addition of salts. An adequate description has been obtained by including the effects of gravity and surface forces in the form of Weber and Froude numbers as well as the effect of electric forces expressed by the value of surface potential.

A treatment of the volume and fluctuation term in Poisson's equation in the Debye-Hückel theory of strong electrolyte solutions

A modified Poisson-Boltzmann equation for symmetrical electrolytes is considered which includes estimates for both the fluctuation potential and the volume term. The equation is solved using a previously developed quasilinearization procedure for 1 : 1 and 2 : 2 electrolytes and the results compared with the Monte Carlo computations. In the 1 : 1 case good agreement is found with the Monte Carlo calculations, the results being on a par with the HNC calculations. In the 2 : 2 case satisfactory qualitative agreement is found with the preliminary findings of the Monte Carlo calculations.

Determination of the supersaturation in crystallization from solution of strong electrolytes

An expression for the exact determination of the driving force (the supersaturation) in the crystallization from solutions of strong electrolytes is submitted. The way for establishing the error involved in the calculation of the supersaturation from the concentration/solubility ratio is shown.