Studies on Apparent Molal Compressibility and Molal Volume of ZnSO4 in Aqueous Saccharides Mixed Solvent Systems: A Comparative Study

Different metal ions as well as carbohydrates play vital role in human metabolism. The present investigation emphasizes on zinc sulphate (ZnSO4) in galactose and its comparative study with lactose in aqueous medium at 303.15, 308.15, 313.15K temperature and at 1.0 atmospheric pressure. Different physical quantities such as density, viscosity and speed of sound have been measured as function of concentrations and temperatures for these multi-component solutions. These quantities were further used to evaluate various thermo-acoustic parameters like acoustic impedance, isentropic compressibility, partial molal compressibility, partial molal volume, internal pressure etc,. The results were analyzed to assess the type and extent of association among the components. Moreover, both Zn2+ and SO42- are in the Hofmeister series and there is a possibility of ion-macro molecule interactions in aqueous solution. The breaking of the structure and the solvation of the solute by changing the temperature in mixed solvents are the point of discussion in the present study. Interestingly, the ion-solvation of zinc ion is comparatively more favorable in galactose than in lactose-water mixed solvent systems. Resumen. Diferentes iones metálicos, así como carbohidratos juegan un papel vital en el metabolismo humano. La presente investigación centra su atención sobre el sulfato de zinc (ZnSO4) en galactosa y un estudio comparativo con lactosa en soluciones acuosas a las temperaturas 303.15, 308.15, 313.15K y 1 atm de presión. Se midieron diferentes cantidades físicas como densidad, viscosidad y velocidad del sonido como función de la concentración y la temperatura de las soluciones. Posteriormente, estas cantidades se utilizaron para evaluar distintos parámetros termoacústicos como impedancia acústica, compresibilidad isoentrópica, compresibilidad molal parcial, volumen molal parcial, presión interna, etc. Los resultados se analizaron para evaluar el tipo y grado de la asociación entre los componentes. Mas aún, tanto Zn2+ como SO42- están en las series de Hofmeister y hay una posibilidad de presencia de interacciones ión-macromolécula en la solución acuosa. Un punto de discusión en el presente estudio es el rompimiento de la estructura y la solvatación del soluto debidos al cambio de la temperatura de las soluciones. Es interesante hacer notar que la solvatación de los iones de zinc es comparativamente mas favorable en las soluciones acuosas de galactosa que de lactosa.

Study of Physical Properties for Sodium acetate with Water and Water - Acetone mixtures at Different Temperatures

In this study binary and ternary solutions are prepared by using the sodium acetate concentrations (0.1, 0.125, 0.2, 0.25, 0.4, 0.5, 0.8, 1 M) in water and acetone –water mixtures .The important parameters such as apparent molal volume, the partial molal volume transfer, apparent molal compressibility, free energy of activation of viscous flow and thermodynamic activation parameter (enthalpy and entropy) determined of sodium acetate in water , 20%, 40% ,60% and 80% V/V acetone –water mixtures at 298.15K, 303.15K, and 308.15K from density and viscosity measurements espectively. The limiting apparent molal volumes and experimental slopes were derived from the Masson equation, have been interpreted in terms of solute–solvent and solute–solute interactions respectively. The viscosity data were analyzed using theJones–Dole equation and the derived parameter B - coefficient has also been interpreted in terms of solute–solvent interactions in the solutions.

Ultrasonic Studies of Some Biomolecules in Aqueous Guanidine Hydrochloride Solutions at 298.15 K

Ultrasonic velocity (U), viscocity (η) and density (ρ) ofL- ascorbic acid, dextrose and sucrose in aqueous guanidine hydrochloride (0.3 m) have been measured at 298.15 K. The derived acoustical parameters namely adiabatic compressibility (β), apparent molal compressibility (ΨK) apparent molal volume (ΨV) limiting apparent molal compressibility (Ψ0K) limiting apparent molal volume (Ψ0V) and their constants (SK, Sv) and viscosityB- coefficient and hydration number (nH) have been computed from the experimental data. The variation of these parameters with respect to the molality of solutes have been explained on the basis of solute-solvent interaction and structure making tendency of the solutes in solvents.

Acoustic and Volumetric Properties of Digoxin and Thiabendazole in 1, 4 Dioxane at 303 K

Acoustical and volumetric properties have been measured for substituted heterocyclic compounds digoxin and thiabendazole in 1, 4 dioxane at 303 K. The ultrasonic velocity measurement have been performed to evaluate acoustical parameter such as adiabatic compressibility (βs), partial molal volume (ɸv), intermolecular free length (Lf), apparent molal compressibility (ɸk), specific acoustic impedance (Z), relative association (RA), salvation number (Sn), limiting apparent molal compressibility (ɸ0k), limiting apparent molal volume(ɸ0v) and their constant (Sk,Sv). The viscosity coefficient (A, B) was evaluated by using john–dole equation. These parameters throw the light on the solute-solvent interaction and solute-solute interaction.

Compressibilities of aqueous electrolyte solutions

The Tammann-Tait-Gibson (TTG) model was used to derive and analyse an equation for the isothermal compressibility of aqueous electrolyte solutions as a function of temperature and pressure. The linear equation of Φk in c½ (Φk is the apparent molal compressibility, c is in mol 1-1) is shown to be inadequate. The best function in the square-root of the concentration [either in (mol kg-1) or c] is degree three. This gives the correct limiting slope predicted by the TTG model, viz., Sv/(BT + 1), where S, is the Masson slope for apparent molal volumes and BT is the Tait parameter for pure water. This slope was verified previously by comparison with the limiting slope obtained experi- mentally, and can be predicted from the standard ionic entropies. The difference in the TTG slope and the Debye-Hiickel point-charge slope is proportional to changes in the reorientation motion of water molecules close to the ionic surface. The electrostriction component, Vcelect, of the limiting partial molal volume is equal to - K°(BT+ 1), where K° is the limiting partial molal compressibility. Values of V°elect calculated from this relationship are compared with values from other models. The TTG model was used to derive internal pressure functions which could be used to analyse deviations of V°elect from the NIH (non-interacting homomorph) model. The TTG equations were used to calculate the isothermal compressibilities of 15 electrolytes. The agreement with experimental values is good (deviations are less than 0.1 × 10-6cm3 g-1 bar-1 for βv for the most reliable data). Values of Φk at 200 bar were calculated also and are in good agreement with the corresponding experimental values.