THE APPARENT MOLAR VOLUME OF SODIUM HYDROXIDE AT INFINITE DILUTION AND THE VOLUME CHANGE ACCOMPANYING THE IONIZATION OF WATER1

1962 ◽  
Vol 66 (1) ◽  
pp. 177-179 ◽  
Author(s):  
Agnes Bodanszky ◽  
Walter Kauzmann
1975 ◽  
Vol 28 (10) ◽  
pp. 2109 ◽  
Author(s):  
RH Stokes

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride are measured up to 2 mol l-1 at 25�C by a combination of pyknometric and dilatometric methods. The apparent molar volume f�V of undissociated ammonia at infinite dilution is found to be 24.85�0.02 cm3 mol-1, and that of NH4Cl is 35.71�0.02 cm3 mol-1. The volume change on ionization for the standard states ΔV� is -29.07�0.04 cm3 mol-1. For aniline the values are: f�V(PhNH2) 89.30, f�V(PhNH3Cl) 102.74 and ΔV� -26.49�0.05 cm3 mol-1.


2010 ◽  
Author(s):  
◽  
Indra Bahadur

The thermodynamic properties of mixtures involving ionic liquids (ILs) with alcohols or alkyl acetate or nitromethane at different temperatures were determined. The ILs used were methyl trioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]+[Tf2N]-) and 1-butyl-3- methylimidazolium methyl sulphate [BMIM]+[MeSO4]-. The ternary excess molar volumes (�������� E ) for the mixtures {methyl trioctylammonium bis (trifluoromethylsulfonyl)imide + methanol or ethanol + methyl acetate or ethyl acetate}and (1-butyl-3-methylimidazolium methylsulfate + methanol or ethanol or 1-propanol + nitromethane) were calculated from experimental density values, at T = (298.15, 303.15 and 313.15) K and T = 298.15, respectively. The Cibulka equation was used to correlate the ternary excess molar volume data using binary data from literature. The �������� E values for both IL ternary systems were negative at each temperature. The negative contribution of �������� E values are due to the packing effect and/or strong intermolecular interactions (ion-dipole) between the different molecules. The density and speed of sound of the binary solutions ([MOA]+[Tf2N]- + methyl acetate or ethyl acetate or methanol or ethanol), (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) were also measured at T = ( 298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. The apparent molar volume, Vφ , and the apparent molar isentropic compressibility, κφ , were evaluated from the experimental density and speed of sound data. A Redlich-Mayer type equation was fitted to the apparent molar volume and apparent molar isentropic compressibility data. The results are discussed in terms of solute-solute, solute- solvent and solvent-solvent interactions. The apparent molar volume and apparent molar isentropic compressibility at infinite dilution, ��φ �� and κφ ��, respectively of the binary solutions have been calculated at each temperature. The ��φ �� values for the binary v systems ([MOA]+[Tf2N]- + methyl acetate or ethyl acetate or methanol or ethanol) and (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) are positive and increase with an increase in temperature. For the (methanol + methyl acetate or ethyl acetate) systems ��φ �� values indicate that the (ion-solvent) interactions are weaker. The κφ �� is both positive and negative. Positive κφ ��, for ([MOA] + [Tf2N]- + ethyl acetate or ethanol), (methanol + ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) can be attributed to the predominance of solvent intrinsic compressibility effect over the effect of penetration of ions of IL or methanol or ethanol. The positive κφ �� values can be interpreted in terms of increase in the compressibility of the solution compared to the pure solvent methyl acetate or ethyl acetate or ethanol. The κφ �� values increase with an increase in temperature. Negative κφ ��, for ([MOA] + [Tf2N]- + methyl acetate or methanol), and (methanol + methyl acetate) can be attributed to the predominance of penetration effect of solvent molecules into the intra-ionic free space of IL or methanol molecules over the effect of their solvent intrinsic compressibility. Negative κφ �� indicate that the solvent surrounding the IL or methanol would present greater resistance to compression than the bulk solvent. The φ �� values decrease with an increase in the temperature. The infinite dilution apparent molar expansibility, ��φ �� , values for the binary systems (IL + methyl acetate or ethyl acetate or methanol or ethanol) and (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) are positive and decrease with an increase in temperature due to the solution volume increasing less rapidly than the pure solvent. For (IL + methyl acetate or ethyl acetate or methanol or ethanol) systems ��φ �� indicates that the interaction between (IL + methyl acetate) is stronger than that of the (IL + ethanol) or (IL + methanol) or (IL + ethyl acetate) solution. For the (methanol + methyl acetate or ethyl acetate) systems ��φ �� values vi indicate that the interactions are stronger than (ethanol + methyl acetate or ethyl acetate) systems.


2013 ◽  
Vol 10 (2) ◽  
pp. 432-441 ◽  
Author(s):  
Baghdad Science Journal

Apparent molar volume, V?, and viscosity B-coefficient of nicotinc acid in water and in aqueous NaCl solutions have been determined from density and viscosity measurements at (293.15, 298.15, 303.15 and 308.15) K. The experimental density data were evaluated by Masson equation, and the derived, apparent molar volume at infinite dilution, Vo?, and the slope Sv, were interpreted in term of solute-solvent and solute- solute interactions. Transfer apparent molar volumes at infinite dilution of nicotinic acid from water to NaCl solutions at various temperatures have been calculated.The viscosity data have been analyzed using Jones-Dole equation, and the derived parameters, Jones-Dolecoefficient, B,and Falkenhagen coefficient,A, have been also interpreted in terms of solute-solvent and solute-solute interactions respectively. The variation of B coefficient with temperature, (dB/dT), was also determined, the negative values indicate that nicotinic acid in aqueous NaCl solution is structure making. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions. The free energy, enthalpy, andentropy of activation were calculated using the Nightingale, Benck, and Eyring equations. Free energies of activation of viscous flow ( *1) per mole, and, ( *2) per mole,of solvent and solute, respectively, were also calculated. The effects of soluteson the structure of water were interpreted in terms of viscositiesand the thermodynamic parameters.


2018 ◽  
Vol 232 (3) ◽  
pp. 393-408 ◽  
Author(s):  
Dinesh Kumar ◽  
Shashi Kant Sharma

AbstractDensities,ρand ultrasonic speeds, u of L-histidine (0.02–0.12 mol·kg−1) in water and 0.1 mol·kg−1aqueous citric acid solutions were measured over the temperature range (298.15–313.15) K with interval of 5 K at atmospheric pressure. From these experimental data apparent molar volume ΦV, limiting apparent molar volume ΦVOand the slopeSV, partial molar expansibilities ΦEO, Hepler’s constant, adiabatic compressibilityβ, transfer volume ΦV, trO, intermolecular free length (Lf), specific acoustic impedance (Z) and molar compressibility (W) were calculated. The results are interpreted in terms of solute–solute and solute–solvent interactions in these systems. It has also been observed that L-histidine act as structure maker in water and aqueous citric acid.


1983 ◽  
Vol 48 (8) ◽  
pp. 2327-2334
Author(s):  
Otakar Söhnel ◽  
Petr Novotný ◽  
Zdeněk Šolc

Two methods are given for assessment of density of binary aqueous solutions of electrolytes; one is based on partial molar volume of the dissolved electrolyte at infinite dilution, and the other is based on additivity of apparent molar volumes at a given concentration. The density estimates of aqueous solutions by means of the two methods are compared with experimental values for some electrolytes of the type 1-1 to 4 and 2-2. In all cases the estimates agree with experimental densities up to concentrations of the saturated solutions.


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