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CHAPTER -IX Apparent Molar Volumes and Viscosity B-Coefficients of Mineral Salts in Aqueous 2-Methoxy ethanol Solutions at T = 298.15 K 9.1. Introduction Mineral salts are naturally-occurring elements needed by the body for its vital activities. Each mineral, with its own specific task, even in the small and often minute quantities necessary, is indispensable for important life functions; they are needed for the formation of hormones, enzymes and other body substances. They’re generally found in foods in the form of chemical compounds called salts and in water in the form of ion soluble. They are needed in very small amounts, or traces, in the diet, and hence their name, "trace minerals. Sodium nitrate is used as an ingredient in fertilizers, pyrotechnics, as an ingredient in smoke bombs, as a food preservative, as a solid rocket propellant, and as in glass and pottery enamels. Potassium nitrate is a strong oxidizer which burns and explodes with organics. It is used in the manufacture of gunpowder. It is also used in explosives, fireworks, matches, and fertilizers, and as a preservative in foods especially meats. It is sometimes used in medicine as a diuretic. Potassium nitrate prill type is mainly used to produce kinescope, optics glass, high grade craft glassware .Lithium nitrate is used as an electrolyte for high temperature batteries. It is also used for long life batteries as required, for example, by artificial pacemakers. The solid is used as a phosphor for neutron detection. 2-Methoxy Ethanol finds a wide range of application 1, namely as a solvent and solubilizing agent in many industries Studies on densities (ρ) and viscosities (η) of electrolyte solutions are of great importance in characterizing the properties and structural aspects of solutions. The addition of an electrolyte to an aqueous organic solution alters the pattern of ion solvation and causes phenomenal changes in the behavior of the dissolved electrolyte. Hence studies on the limiting apparent molar volume and viscosity–B coefficients of electrolyte provide us valuable information regarding ion- Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 252 ion, ion-solvent and solvent-solvent interactions 2–4. It has been found by a number of workers 5–7 that the addition of an electrolyte could either make or break the structure of a liquid. As the viscosity of a liquid depends on the intermolecular forces, the structural aspects of the liquid can be inferred from the viscosity of solutions at various electrolyte concentrations. The studies of partial molar volumes are of great help in characterizing the structure and properties of solutions. The solution structure is of great importance in understanding the nature of the action of bioactive molecules in the body system. The addition of an organic solvent to water brings about a sharp change in the solvation of ions. The peculiarities of aqueo-organic mixtures are well reflected in the dramatic changes in reaction rates 8, 9 and medium effect or free energies of transfer of ions which cannot be explained on the basis of change in the dielectric constants of the solvent mixtures alone. As the partial molar volume of a solute reflects the cumulative effects of ion–ion and ion–solvent interactions, it would be of interest to study the partial molar volumes of Mineral salts, viz. sodium nitrate, potassium nitrate and lithium nitrate in the binary aqueous mixtures of 2-methoxy ethanol. Such data are expected to highlight the role of mineral salts in influencing the partial molar volumes in mixed solvent systems. These considerations prompted us to undertake the present study 9.2. Experimental Section Materials Sodium nitrate (Ranbaxy, >98.0%) was crystallized from hot water, cooled to 00C and dried under vacuum at 1400C, potassium nitrate (S.D. fine Chemicals, >99.5%), was crystallized from hot water, cooled and dried for 12hr under vac. at 700C. Lithium nitrate (Thomas Baker, >98%) was crystallized from ethanol and dried at 1800C for several days by repeated melting under vac. The anhydrous salt was dried at 1200C and stored in a vacuum desiccator over calcium Sulphate. 2methoxy ethanol (SRL, India, >99.5%) was refluxed with stannous chloride. It was dried with silica gel and finally distilled with sodium. De-ionized, doubly distilled, degassed water with a specific conductance of 1· 10 −6 S ⋅ cm −1 was used for the Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 253 preparation of different aqueous 2-methoxy ethanol solutions. The physical properties of different aqueous 2-methoxy ethanol solutions are listed in Table 1 Apparatus and Procedure The density, ρ , was measured with an Anton Paar density-meter (DMA 4500M). The uncertainty in the density measurements is within ± 5·10-5 g·cm-3. It was calibrated by double-distilled water and dry air. The viscosity,η , was measured by means of suspended Ubbelohde type viscometer, calibrated at the experimental temperatures with doubly distilled water and purified methanol. A thoroughly cleaned and perfectly dried viscometer filled with experimental solution was placed vertically in a glass-walled thermostat (Bose Panda Instruments Pvt. Ltd.) maintained to ± 0.01 K. After attainment of thermal equilibrium, efflux times of flow were recorded with a stop watch correct to ± 0.1 s. At least three repetition of each data reproducible to ± 0.1 s were taken to average the flow time. Viscosity of solution,η, is given by the following equation: η = (Kt − L / t)ρ (1) where K and L are the viscometer constants and t and ρ are the efflux time of flow in seconds and the density of the experimental liquid, respectively. The uncertainty in viscosity measurements is within ± 0.003 mPa·s. The electrolyte solutions studied here were prepared by mass. The experimental values of molality, densities, viscosities, apparent molar volume and (ηr − 1) are reported in Table 2. m 9.3. Results and Discussion The apparent molar volumes ( φV ) were determined from the solution densities using the following equation10: φV = M ρ − 1000(ρ − ρ0 ) mρρ0 (2) where M is the molar mass of the solute, m is the molality of the solution, ρ 0 and ρ are the densities of the solvent and the solution respectively. As the plots of Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 254 φV values against square root of molality ( m ) were linear, φV values were fitted to the Masson equation 11: φV = φV0 + SV* m (3) where φV0 is the limiting apparent molar volume at infinite dilution, SV* is the experimental slope and m is the molality of the solution. The φV0 values have been determined by fitting the dilute data (m < 0.1mol·kg-1) to eq.3 using a weighted least square fit. The standard deviation ( σ ) were determined from φV0 values using the following equation: σ = ∑ (Y exp − Ycal) N −1 2 ( 4) where Y is the limiting apparent molar volume of the solution ( φV0 ) and N is the number of data points. Values of φV0 and SV* along with the corresponding standard deviation ( σ ) are listed in Table 3. The estimated uncertainties in φV0 are equal to standard deviation ( σ ), the root mean square of the deviation between the experimental and calculated φV0 for each data point. A perusal of Table 3 and Figure 1-3 reveals that the φV0 values of studied salts are positive and increases with rise in the mass percent of 2-methoxy ethanol in the solvent mixture. This indicates the presence of strong ion–solvent interactions and these interactions are strengthened at higher concentrations of 2methoxy ethanol in the solvent mixture. It may be concluded that for all the studied solvent mixtures that the salts are rather solvated than hydrated by 2-methoxy ethanol and the solvation of the salts with the increasing concentration of 2 methoxy ethanol follows the order: K+ > Na+ > Li+ The same results were observed for some thiocyanate in aqueous 1,3-dioxolane mixture 12,13. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 255 Table 3 and Figure 4-6 also reveals that SV* values are negative for all the solutions and SV* values decrease as the amount of 2-methoxy ethanol in the mixtures increases. Since SV* is a measure of ion–ion interactions, the results indicate the presence of weak ion–ion interactions in the solutions at all experimental temperatures, and these interactions further decrease with a rise in concentration of 2-methoxy ethanol in the mixtures. In other words, it may be said that the solvation of electrolyte/ions increases with an increase of 2-methoxy ethanol content in water. This is probably due to moderate dielectric constants 14 of the aqueous 2-methoxy ethanol mixtures, resulting in diminishing ion–ion interactions (ionic dissociation) 15. Here, the structure and properties of mixture as solvent plays an important role. Dielectric constant of pure 2-methoxy ethanol is 17.65, that of water 78.35 and that of mixture is between these two values. According to the coulombic law of ion-ion interactions are stronger at lower dielectric constant. These negative values of SV* in different compositions of 2methoxy ethanol + water also suggest the presence of cation–anion penetration 16 and this happens due to the competition between the ions to occupy the void space of the large solvent molecules. A quantitative comparison of the magnitude of values shows φV0 values are much greater in magnitude than SV* values, for all the solutions. This suggests that ion-solvent interactions dominate over ion–ion interactions in all the solutions. Partial molar volumes ∆φV0 of transfer from water to different aqueous 2methoxy ethanol solutions have been determined using the relations 17,18. ∆φV0 = φV0 (Aqueous 2 − methoxy ethanol solution) − φV0 (Water) (5) The ∆φV0 value is independent of ion-ion interactions and therefore provides information regarding ion-solvent interactions 17. It can be seen from Table 5, Figure 7-9 that the value of ∆φV0 is positive and increases monotonically with mass percent of 2-methoxy ethanol in the remaining mixture. These results further confirm the presence of strong ion-solvent interaction in the chosen solvent mixture for mineral Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 256 salts. On the other hand with the increase of the size of the cation of the mineral salts the ∆φV0 also increases i.e. the ion solvent interaction also increases with the increases of the size of cation of the mineral salts. The viscosity data of the experimental solutions of carbohydrates have been analyzed using the Jones–Dole equation 19: (η η0 − 1) m = (ηr − 1) m = A+ B m (6) where, the relative viscosity ηr = η η0 , η0 and η are the viscosities of the solvent and solution, respectively, and m is the molality of a solution. A and B are the Jones-Dole 19 constants estimated by a least-squares method and reported in Table 4. The values of the A coefficient are found to be smaller than the viscosity Bcoefficient and it decrease with increase in mass of 2-methoxy ethanol in the solvent mixture. These results indicate the presence of very weak ion–ion interactions and these interactions further decrease with an increase in mass percent of 2-methoxy ethanol in solvent mixture. These results are in excellent agreement with those obtained from SV* values. The viscosity B-coefficient 20, 21 reflects the effects of ion–solvent interactions on the solution viscosity. The viscosity B-coefficient is a valuable tool to provide information concerning the solvation of solutes and their effects on the structure of the solvent in the local vicinity of the solute molecules. From Table 4 it is evident that the values of the B-coefficient of mineral salts in the studied solvent systems suggests the presence of strong ion–solvent interactions, and these type of interactions are strengthened with an increase of 2-methoxy ethanol in the solvent mixtures. These conclusions are in excellent agreement with those drawn from φV0 values discussed earlier. The viscosity data have also been analyzed on the basis of transition state theory for the relative viscosity of the solutions as suggested by Feakins et al. 22 using the relation, ∆µ20 ≠ = ∆µ10≠ + RT (1000 B + φ20 − φ10 ) / φ10 (7) Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 257 where φ10 and φ20 are the limiting apparent molar volumes of the solvent and solute, respectively. The contribution per mole of the solute to the free energy of activation of viscous flow, ∆µ 20 ≠ of the solutions was determined from the above relation and is listed in Table 6. The free energy of activation of viscous flow for the solvent mixture, ∆µ10 ≠ , is given by the relation: ∆µ10≠ = ∆G10≠ = RT ln(η0 φ10 hN A ) (8) where NA is the Avogadro’s number, ∆G10 ≠ is the Gibb’s free energy of viscous flow, η0 is the viscosity of the solvent mixture, φ10 is the limiting apparent molar volume of the solvent and h is the Planks Constant. The values of the parameters ∆µ10 ≠ and ∆µ 20 ≠ are reported in Table 6 and the values suggest that ∆µ10 ≠ is almost invariant of the solvent compositions, implying that ∆µ20 ≠ is dependent mainly on the viscosity B-coefficients and (φV0, 2 − φV0,1 ) terms. But ∆µ20 ≠ values were found to be positive at all mass percent and this suggests that the process of viscous flow becomes difficult as the size of the cation and mass percent of the 2-Methoxy Ethanol increase. Hence the formation of the transition state becomes less favorable 22. According to Feakings et. al 23 ∆µ20 ≠ > ∆µ10 ≠ for solutes having positive viscosity B-coefficients and indicates a stronger ion-solvent interactions, thereby suggesting that the formation of transition state is accompanied by the rupture and distortion of the intermolecular forces in solvent structure 22. 9.4. Conclusion: In summary, φV0 and viscosity B-coefficient values for studied mineral salts indicate the presence of strong solute-solvent interactions and these interactions are further strengthened at higher mass percent of 2-methoxy ethanol in the solvent mixture. In case of potassium nitrate the solute-solvent interaction is greater than the sodium nitrate and lithium nitrate respectly with higher mass percent of the 2methoxy ethanol in the solvent mixture. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 258 References 1. G. Roux, G. Perron, J. E. Desnoyers, J. Solution Chem. 1978, 7, 639. 2. J. M. Mc Dowali, C. A. Vincent, J. Chem. Soc. Faraday Trans. I, 1974, 1862. 3. M. R. J. Dack, K. J. Bird, A. J. Parker, Aust. J. Chem. 1975, 28, 955. 4. M. N. Roy, B. Sinha, R. Dey, A. Sinha, Int. J. Thermophys. 2005, 26, 1549. 5. R. H. Stokes, R. Mills, Int. Encyclopedia of Physical Chemistry and Chemical Physics, 1965. 6. P. S. Nikam, H. Mehdi, J. Chem. Eng. Data 1988, 33, 165. 7. D. Nandi, M. N. Roy, D. K. Hazra, J. Indian Chem. Soc. 1993, 70, 305. 8. D. W. Wells, in: A. K. Covington, T. Dickinson (Eds.), Physical Chemistry of Organic Solvent Systems, Plenum Press, London, 1973, Ch. 6. 9. M. J. Blandamer, J. Burgess, B. Clark, P. P. Duce, A. W. Hakin, N. Gosal, S. Radulovic, P. Guardado, F. Sanchez, C.D. Hubbard, E.A. Abu-Gharib, J. Chem. Soc. Faraday Trans. I. 1986, 82, 1471. 10. E. Ayranci J. Chem. Eng. Data 1997, 42, 934. 11. D. O. Masson, Philos. Mag. 1929, 8, 218. 12. M. N. Roy, A.Choudhury, A. Jha, J. Chem. Eng. Data 2004, 49 291 13. M. N. Roy, R. Chanda, A. Banerjee, J. Chem. Eng. Data 2009, 54 (6), 1767. 14. P. R. Misra, B. Das, M. L. Parmar, D. S. Banyal, Indian J. Chem. 2005, 44, 1582. 15. F. J. Millero, Structure and Transport Process inWater and Aqueous Solutions R. A. Horne, New York, 1972. 16. M. L. Parmar, S. Mahajan, Acta Cienc. Indica 1, 1984, 31. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 259 17. K. Belibagli, E. Agranci, J. Solution Chem. 1990, 19, 867. 18. Zhao, P. Ma, J. Li, J. Chem. Thermodyn. 2005, 37, 37 19. G. Jones, M. Dole, J. Am Chem. Soc. 1929, 51, 2950. 20. F .J. Millero The Molal Volumes of Electrolytes. Chem. Rev. 1971, 71, 147. 21. F. J. Millero, A. Lo Surdo, C. Shin, J. Phys. Chem. 1978, 82, 784. 22. D. Feakins, D. J. Freemantle, K. G. Lawrence, J. Chem. Soc., Faraday Trans. I, 1974, 70, 795. 23. A. N. Campbell, R. J. Friesen, Can. J. Chem. 1959, 37, 1288. 24. M. Pilar Pena, Ernesto Vercher, and Antoni Martinez-Andreu J. Chem. Eng. Data 1998, 43, 626. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 260 Table 1. Densities ( ρ ) and Viscosities (η ) of 2-Methoxy Ethanol (1) + Water (2) Solutions at 298.15 K Solvent mixtures ρ .10-3 /kg ⋅ m −3 η/mPa ⋅ s 298.15 0.9993 1.1812 298.15 0.99832 2.3159 298.15 0.99712 2.9561 T(K) 10 mass % of 2-methoxy ethanol + water 40 mass % of 2-methoxy ethanol + water 70 mass % of 2-methoxy ethanol + water Table 2. Molalities ( m ), Densities ( ρ ), Viscosities (η ), Apparent Molar Volumes ( φV ) and (ηr − 1) / m for Mineral Salts in Different Molality (m1) of 2-methoxy Ethanol (1) + Water (2) Solutions at 298.15 K m / mol ⋅ kg -1 ρ ⋅ 10-3 /kg ⋅ m −3 η/mPa ⋅ s φV ⋅ 106 / m 3 ⋅ mol −1 (ηr − 1) m 10 mass % of 2-methoxy ethanol + water Lithium nitrate 0.0225 0.0299 0.0525 0.0674 0.0824 0.0937 1.0002 1.0005 1.0014 1.0020 1.0026 1.0030 1.186 1.188 1.190 1.192 1.194 1.195 Sodium nitrate 29.41 29.32 29.20 29.07 29.03 28.92 0.0293 0.0322 0.0352 0.0370 0.0380 0.0382 0.0242 0.0323 0.0566 0.0727 0.0889 0.1010 1.0006 1.0010 1.0023 1.0032 1.0040 1.0046 1.187 1.189 1.192 1.195 1.196 1.198 Potassium nitrate 32.07 31.97 31.81 31.71 31.60 31.51 0.0320 0.0353 0.0390 0.0430 0.0420 0.0447 0.0240 0.0320 0.0560 0.0720 0.0881 0.1007 1.0007 1.187 42.32 1.0012 1.189 42.05 1.0026 1.193 41.69 1.0036 1.195 41.31 1.0046 1.197 41.07 1.0053 1.199 41.01 40 mass % of 2-methoxy ethanol + water 0.0340 0.0363 0.0415 0.0444 0.0460 0.0480 Lithium nitrate 0.0241 0.9993 2.327 29.97 0.0304 Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 261 0.0322 0.0563 0.0724 0.0885 0.1005 0.9996 1.0005 1.0012 1.0018 1.0023 2.330 2.338 2.341 2.345 2.346 Sodium nitrate 29.88 29.57 29.43 29.31 29.25 0.0340 0.0396 0.0410 0.0425 0.0418 0.0240 0.0320 0.0560 0.0720 0.0880 0.1000 0.9996 1.0000 1.0013 1.0021 1.0030 1.0036 2.328 2.331 2.339 2.344 2.349 2.353 Potassium nitrate 32.65 32.55 32.23 32.09 31.94 31.85 0.0344 0.0375 0.0415 0.0455 0.0480 0.0508 0.0240 0.0320 0.0560 0.0720 0.0880 0.1001 0.9997 2.330 43.32 1.0002 2.333 42.96 1.0016 2.342 42.30 1.0026 2.349 41.82 1.0036 2.358 41.56 1.0043 2.360 41.39 70 mass % of 2-methoxy ethanol + water 0.0394 0.0420 0.0480 0.0529 0.0580 0.0604 Lithium nitrate 0.0246 0.0328 0.0573 0.0737 0.0901 0.1024 0.9980 0.9984 0.9994 1.0000 1.0007 1.0012 2.972 2.976 2.986 2.993 3.000 3.006 Sodium nitrate 30.76 30.58 30.29 29.99 29.83 29.71 0.0350 0.0380 0.0428 0.0468 0.0500 0.0527 0.0241 0.0321 0.0562 0.0723 0.0883 0.1004 0.9984 0.9988 1.0000 1.0009 1.0018 1.0024 2.974 2.977 2.989 2.997 3.007 3.013 Potassium nitrate 33.81 33.57 33.08 32.89 32.69 32.53 0.0389 0.0404 0.0473 0.0520 0.0580 0.0611 0.0240 0.0320 0.0560 0.0720 0.0880 0.1000 0.9985 0.9989 1.0004 1.0014 1.0023 1.0031 44.37 43.98 42.96 42.48 42.13 41.92 0.0452 0.0469 0.0567 0.0623 0.0650 0.0780 2.977 2.981 2.996 3.005 3.013 3.029 Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 262 Table 3. Limiting Apparent Molar Volumes ( φV o ) and the Experimental Slopes ( SV* ) of Eq. 3 for Mineral salts along with the Standard Deviation ( σ ) in Different Molality (m1) of 2-Methoxy ethanol (1) + Water (2) Solutions at 298.15 K Solvent mixtures φV o ⋅ 106 /m3 ⋅ mol−1 SV* .106 /(m9 ⋅ mol−3 )1/ 2 Lithium nitrate σ 0 mass % of 2-methoxy ethanol 27.80 a - - 10 mass % of 2-methoxy ethanol 29.85 -2.96 0.0003 40 mass % of 2-methoxy ethanol 30.68 -4.58 0.0003 70 mass % of 2-methoxy ethanol 31.76 -6.40 0.0000 Sodium nitrate 0 mass % of 2-methoxy ethanol 28.22 b - - 10 mass % of 2-methoxy ethanol 32.58 -3.30 0.0002 40 mass % of 2-methoxy ethanol 33.43 -5.03 0.0000 70 mass % of 2-methoxy ethanol 34.99 -7.79 0.0000 Potassium nitrate 0 mass % of 2-methoxy ethanol 38.28 a - - 10 mass % of 2-methoxy ethanol 43.35 -7.71 0.0018 40 mass % of 2-methoxy ethanol 44.70 -11.58 0.0026 70 mass % of 2-methoxy ethanol 46.01 -15.09 0.0060 a Value obtained from density data reported Ref 23. b Values taken from Ref 24. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 263 Table 4. Values of Viscosity A and B Coefficients derived from Eq.6 for Mineral salts in Different Molality (m1) of 2-Methoxy ethanol (1) + Water (2) Solutions at 298.15 K Solvent mixtures B /L ⋅ mol−1 A /L1/2 ⋅ mol−1/2 Lithium nitrate 10 mass % of 2-methoxy ethanol 0.056 0.022 40 mass % of 2-methoxy ethanol 0.073 0.020 70 mass % of 2-methoxy ethanol 0.105 0.018 Sodium nitrate 10 mass % of 2-methoxy ethanol 0.073 0.021 40 mass % of 2-methoxy ethanol 0.097 0.019 70 mass % of 2-methoxy ethanol 0.139 0.016 Potassium nitrate 10 mass % of 2-methoxy ethanol 0.086 0.021 40 mass % of 2-methoxy ethanol 0.131 0.018 70 mass % of 2-methoxy ethanol 0.183 0.015 Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 264 Table 5. Partial molar volumes of transfer from water to different aqueous 2Methoxy ethanol solutions for NaNO3, KNO3 at 298.15 K. Solvent mixtures φV0 × 106 / m3 ⋅ mol−1 ∆φV0 × 106 / m 3 ⋅ mol −1 Lithium nitrate 0 mass % of 2-methoxy ethanol 27.80 a 0.00 10 mass % of 2-methoxy ethanol 29.85 2.05 40 mass % of 2-methoxy ethanol 30.68 2.88 70 mass % of 2-methoxy ethanol 31.76 3.96 Sodium nitrate 0 mass % of 2-methoxy ethanol 28.22 b 0.00 10 mass % of 2-methoxy ethanol 32.58 4.36 40 mass % of 2-methoxy ethanol 33.43 5.21 70 mass % of 2-methoxy ethanol 34.98 6.76 Potassium nitrate 0 mass % of 2-methoxy ethanol 38.28 a 0.00 10 mass % of 2-methoxy ethanol 43.35 5.06 40 mass % of 2-methoxy ethanol 44.70 6.41 70 mass % of 2-methoxy ethanol 46.01 7.73 Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 265 Table-6: Values of (φV0,2 − φV0,1 ) , ∆µ10 ≠ , ∆µ 20≠ for mineral salts in aqueous 2-methoxy ethanol solutions at 298.15 K. Parameters Lithium nitrate Sodium nitrate Potassium nitrate 10 mass % of 2-methoxy ethanol (φV0,2 − φV0,1 ) ⋅106 / m3 ⋅ mol−1 -3.95 3.76 14.53 ∆µ10≠ /( kJ ⋅ mol −1 ) 11.02 11.02 11.02 ∆µ 20≠ /( kJ ⋅ mol −1 ) 15.50 17.67 19.63 40 mass % of 2-methoxy ethanol (φV0,2 − φV0,1 ) ⋅106 / m3 ⋅ mol−1 -2.76 4.59 15.85 ∆µ10≠ /( kJ ⋅ mol −1 ) 12.69 12.69 12.69 ∆µ 20≠ /( kJ ⋅ mol −1 ) 18.69 21.48 25.31 70 mass % of 2-methoxy ethanol (φV0,2 − φV0,1 ) ⋅106 / m3 ⋅ mol−1 -2.10 6.00 17.03 ∆µ10≠ /( kJ ⋅ mol −1 ) 13.31 13.31 13.31 ∆µ 20≠ /( kJ ⋅ mol −1 ) 22.14 25.71 30.42 Figures: Figure 1: Plot of φV0 × 106 / m 3 ⋅ mol −1 of lithium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 266 Figure 2: Plot of φV0 × 106 / m 3 ⋅ mol −1 of Sodium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K Figure 3: Plot of φV0 × 106 / m 3 ⋅ mol −1 of Potassium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 267 Figure 4: Plot of SV* × 106 / ( m 9 ⋅ mol −3 )1/ 2 of lithium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K Figure 5: Plot of SV* × 106 / ( m 9 ⋅ mol −3 )1/ 2 of sodium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 268 Figure 6: Plot of SV* × 106 / ( m 9 ⋅ mol −3 )1/ 2 of potassium nitrate as a function of mass percent of 2-methoxy ethanol in different binary mixture of 2-methoxy ethanol + water at 298.15K. Figure 7: Plots of partial molar volumes of transfer ( ∆φV0 × 10 6 / m 3 ⋅ mol −1 ) from water to different aqueous 2-methoxy ethanol solutions for lithium nitrate at 298.15K. Apparent Molar ……………… 2-Methoxy ethanol Solutions at T = 298.15 K 269 Figure 8: Plots of partial molar volumes of transfer ( ∆φV0 × 10 6 / m 3 ⋅ mol −1 ) from water to different aqueous 2-methoxy ethanol solutions for sodium nitrate at 298.15K. Figure 9: Plots of partial molar volumes of transfer ( ∆φV0 × 106 / m 3 ⋅ mol −1 ) from water to different aqueous 2-methoxy ethanol solutions for potassium nitrate at 298.15K.