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1 American Journal of Energy Science 2015; 2(4): Published online June 10, 2015 ( Thermodynamic and Interactions Studies of Serine with Aqueous Sodium Chloride at Different Concentrations, Constant Temperature and Constant Frequency at 2MH z Shilpa A. Mirikar 1, *, Govind K. Bichile 2 1 Department of Physics, Dayanand Science College, Latur (MS), India 2 Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (M.S), India address d001shilpa@gmail.com (S. A. Mirikar), govind_bichile@gmail.com (G. K. Bichile) To cite this article Shilpa A. Mirikar, Govind K. Bichile. Thermodynamic and Interactions Studies of Serine with Aqueous Sodium Chloride at Different Concentrations, Constant Temperature and Constant Frequency at 2MH z. American Journal of Energy Science. Vol. 2, No. 4, 2015, pp Abstract There are many techniques available to study physical properties to interpret the molecular interaction in liquids, liquid mixtures and solutions. The study of ultrasonic waves through solution is found to be quite interesting. The study of ultrasonic waves through solution is used for knowing the nature and strength of intermolecular forces and their interaction in liquids, liquid mixtures and solutions. Thermo-acoustical and its allied properties are very helpful in predicting the physico-chemical behavior and molecular interactions occurring in liquids, liquid mixtures and solutions. Hence this motivates the researchers to take up the research project in the field. Ultrasonic velocity, density and viscosity have been measured for serine in aqueous sodium chloride at different concentrations,constant temperature and constant frequency at 2MH z with a view to investigate the exact nature of molecular interactions. From the experimental data, ultrasonic parameters such as classical absorption factor (α/f 2 ), relaxation time (τ), relaxation strength (r) and Rao s molar sound function (F) have been computed. The results have further been used to interpret the nature and strength of molecular interactions of serine in aqueous NaCl solutions. Keywords Ultrasonic Velocity, Hydrogen Bonding, Molecular Interactions 1. Introduction The present work is a research programmed on thermodynamic, thermo-acoustic and transport behavior of binary liquid mixtures of industrially important components [1]-[3]. In recent years, ultrasonic technique has become a powerful tool in providing information regarding the molecular behavior of liquids and liquid mixtures owing to its ability of characterizing physicochemical behavior of the medium [4],[5]. When two or more liquids are mixed, there occur some changes in physical and thermodynamic properties because of change in volume, energy and molecular interactions. Ultrasonic velocity measurements in liquids provides an information about inter and intra molecular interactions. Thermodynamic parameters derived from the experimental data are extremely used to study the molecular interactions in liquid systems, aqueous solutions and liquid mixtures. In recent years, there has been considerable progress in the determination of thermodynamic, acoustic and transport properties of liquid systems from density and velocity measurements [6], [7]. The measurements of density, ultrasonic velocity, viscosity and the thermodynamic properties derived from these are excellent tools to detect solute-solute and solute-solvent interactions. Even though the ultrasonic velocity data do not provide enough information about the native and the relative strength of various types of intermolecular interionic interactions between the components, their derived parameters such as classical absorption factor (α/f 2 ), relaxation time (τ), relaxation strength (r) and Rao s molar sound function (F) are very useful in the study of molecular interactions. In view of the above we have carried out systematic experimental

2 109 Shilpa A. Mirikar and Govind K. Bichile: Thermodynamic and Interactions Studies of Serine with Aqueous Sodium Chloride at Different Concentrations, Constant Temperature and Constant Frequency at 2MH z investigations of the ultrasonic velocity, density and viscosity measurements of serine in aqueous NaCl at different concentrations at constant temperature. Here we have reported experimental and thermodynamic parameters of serine with aqueous NaCl system. System I- Aqueous NaCl +Serine System II- Aqueous MgCl 2 + Serine The classical absorption factor (α/f 2 ), relaxation time (τ), relaxation strength (r) and Rao s molar sound function (F) were serine in aqueous solution of inorganic salts (electrolytes) such as NaCl and MgCl 2 at K have been studied in the present paper. Such data are expected throw light on the interaction between inorganic salts and biomolecules. 2. Materials and Methods All the chemicals used were of AR grade and dried over anhydrous CaCl 2 in desiccators before use. All solutions were prepared in deionized and distilled water (degassed by boiling), having specific conductivity ~ 10-6 S cm -1. The stock solutions of 1M concentration were prepared by weighing the serine on a digital balance with an accuracy of ± 1 x 10-4 g. Solutions of NaCl & MgCl 2 were made by mass on the mole fraction scale. Uncertainties in solution concentrations were estimated at ± 1 x 10-5 mol kg -1 in calculations. The solutions were kept in the special air tight bottles and were used within 12 hrs after preparation to minimize decomposition due to bacterial contamination. Ultrasonic velocity was measured with a single crystal interferometer (F- 81, Mittal Enterprises, New Delhi) at 2MH z.the interferometer was calibrated against the ultrasonic velocity of water used at T = K. The present experimental value is ms -1 which is in good agreement with literature value ms -1. Accuracy in the velocity measurement was ± 1.0 ms -1. The density measurements were performed with recalibrated specific gravity bottle with an accuracy of ± 2x10-2 kg m -3. An average of triple measurements was taken into account. Sufficient care was taken to avoid any air bubble entrapment. Viscosity was measured with recalibrated Ostwald type viscometer. The flow of time was measured with a digital stop watch capable of registering time accurate to ± 0.1 s. An average of three or four sets of flow of times for each solution was taken for the purpose of calculation of viscosity. The accuracy of the viscosity measurements was ± 0.5 %. Accuracy in experimental temperature was maintained at ± 0.1K by means of thermostatic water bath. 3. Results and Discussion From the measured values ultrasonic velocity(u), density(ρ) and viscosity (η) various acoustical parameters such as the classical absorption factor (α/f 2 ), relaxation time (τ),relaxation strength (r) and Rao s molar sound function (F) were calculated by using the following relations[8]-[11] Ultrasonic velocity u= n λ (1) Density ρ = m / v (2) Viscosity η 2 = [t 2 / t 1 ]. [ρ 2 / ρ 1 ] x η 1 (3) Where, n & λ are frequency and wavelength; v is the volume of the solution; η 1 & η 2 are the viscosities of the water and solutions; t 1, t 2 are time of flow of water and solution and ρ 1, ρ 2 are the densities of water and solution. Classical absorption factor (α/f 2 ) = 2π 2 η/3ρc 2 (4) Relaxation time (τ) = 4η/3ρu 2 (5) Relaxation strength (r) = 1 (u / u ) (6) Rao s molar sound function (F) =M/ ρ (u) 1/3 (7) The experimentally measured values of ultrasonic velocity (u), density (ρ) and viscosity (η) of the solutions and calculated values of acoustical parameters such as classical absorption factor (α/f 2 ), relaxation time (τ),relaxation strength (r) and Rao s molar sound function (F) are reported in Table.1 for the system (water + NaCl +serine) and Table.2 for the system (water+ MgCl 2 + serine) respectively, and the graph plotted for ultrasonic velocity(u), classical absorption factor (α/f 2 ), relaxation time (τ),relaxation strength (r) and Rao s molar sound function (F) at different temperature and various concentrations at 2 MH z frequency for the system (water + NaCl+ serine) and (water+ MgCl 2 + serine) are shown in Fig.1 to Fig. 10 respectively. Table 1. Variation of thermodynamic parameters at different mole fractions (x) and constant temperature for the system (Water + NaCl + Serine) at 2MH z. m mol kg -1 u ms -1 ρ Kg m -3 η Nm -2 s K. α/f 2 x10-15 τ x s 2 m -11 sec r F x10-3 (m/mol)m/s 1/3 Where m, mole fraction; ρ, density of the solution ; η,viscosity of solution; u, ultrasonic velocity; α/f 2 classical absorption factor; τ, relaxation time; r, relaxation strength; F, Rao s molar function.

3 American Journal of Energy Science 2015; 2(4): Table 2. Variation of thermodynamic parameters at different mole fractions (x) and constant temperature for the system (Water + MgCl 2 + Serine) at 2MHz K. m u ρ η α/f 2 x10-15 τ x F x10-3 mol kg -1 ms -1 Kg m -3 Nm -2 s s 2 m -11 r sec (m/mol)m/s 1/ Where m, mole fraction; ρ, density of the solution ; η,viscosity of solution; u, ultrasonic velocity; α/f 2 classical absorption factor; τ, relaxation time; r, relaxation strength; F, Rao s molar function. Fig. 1. Plot of ultrasonic velocity (u) against mole fraction (m) for the system (water + NaCl + serine) at 2MH z and at K temperature. Table. 1for the system (water + NaCl +serine) and Table.2 for the system (water+ MgCl 2 + serine).from Tables, it is seen that ultrasonic velocity increases with increase in concentration of solutes serine. The variation of ultrasonic velocity in a solution depends on the intermolecular free length (L f ). Intermolecular free length is a predominant factor, as it determines the sound velocity in fluid state. Presence of an ion alters the intermolecular free length. Therefore, ultrasonic velocity of a solution will be different from that of the solvent. According to model proposed by Erying and Kincaid [12]- [15] the increase in ultrasonic velocity with the decrease in intermolecular free length (L f ) and vice versa, Ultrasonic velocity (u) is related to intermolecular free length. As the free length decreases due to the increase in concentrations, the ultrasonic velocity has to increase and vice-versa. The experimental results support the above statement in both the cases. Consequently ultrasonic velocity of system increases depending on the structural properties of solutes. The solute that increases the ultrasonic velocity is of structure maker type (SM). The variations in ultrasonic velocity with molar concentrations of NaCl and MgCl 2 in 1M serine are given in Tables.1&2. From Table. 1 -& Fig.1 (water + NaCl + serine) and from Table.2 & Fig.2 (water+ MgCl 2 + serine), it is seen that ultrasonic velocity in aqueous NaCl solution increases with increase in concentration of solutes serine. The value of ultrasonic velocity of serine in aqueous NaCl is less as compared to the value of serine in aqueous MgCl 2. Such an increase in ultrasonic velocity clearly shows that molecular association is being taking place in these liquid systems. The same results are observed for aqueous MgCl 2. The order of variation of ultrasonic velocity with increase in concentrations and temperature is observed as follows; u water < u NaCl < u MgCl 2 Fig. 2. Plot of ultrasonic velocity (u) against mole fraction (m) for the system (water +MgCl 2 +serine) at 2MH z and at K temperature Ultrasonic Velocity (u) The ultrasonic velocity (u), for amino acid, electrolytes solutions at 2MH z frequency, for different temperature and various concentrations (m) have been determined using Eq. (1) and experimental values of u have been presented in Such type of variation in the sound velocity is attributed to different types of interactions taking place in the solutions. These interactions are as follows. a) Ionic group of serine i.e. zwitter ionic centers of serine with Na +, Cl - and Mg ++ ions. b) NH 2 group (hydrophilic) of serine through H-bonding. c) CH 3 -CH-OH group (hydrophobic) of serine, non polar molecules. d) COO - and NH 3 or NH 2 of serine and ions of solvents.

4 111 Shilpa A. Mirikar and Govind K. Bichile: Thermodynamic and Interactions Studies of Serine with Aqueous Sodium Chloride at Different Concentrations, Constant Temperature and Constant Frequency at 2MH z These different types of interactions affect the solute solvent interactions. The factors apparently responsible for such behavior may be the presence of interaction caused by the proton transfer reactions of amino acid and hydrophilic nature of aqueous NaCl and MgCl 2.with variation in concentration and temperature. The ultrasonic velocity increases with molar concentration of solute as well as rise in temperature. The increase in ultrasonic velocity in water, in aqueous NaCl and in aqueous MgCl 2 may be attributed to the overall increase in cohesion brought about by the solutesolute, solute-solvent and solvent-solvent interactions [16] Density (ρ) Density is a measure of solvent-solvent and ion-solvent interactions. Increase of density with concentration indicates the lesser magnitude of solute-solvent and solvent-solvent interactions. Increase in density with concentration is due to the shrinkage in the volume which in turn is due to the presence of solute molecules. In other words, the increase in density may be interpreted to the structure-maker of the solvent due the added solute. Similarly, the decrease in density with concentration indicates structure-breaker of the solvent. It may be also true that solvent-solvent interactions bring about a bonding, probably H-bonding between them. So, size of the resultant molecule increases and hence there will be decrease in density. Density of the solution in both the systems increases with increase in concentration of serine.however, from Table.1(water + NaCl +serine ) and Table.2(water+ MgCl 2 + serine ), density of the solution is less in aqueous NaCl for serine as compared to aqueous MgCl 2 for serine.the order of variation of density with increase in temperatures is observed as follows; Fig. 3. Plot of classical absorption factor (α/f 2 ) against mole fraction for the system (water + NaCl + serine) at 2MH z and at K temperature Viscosity (η) ρ MgCl2 > ρ NaCl > ρ water Viscosity is an important parameter in understanding the structure as well as molecular interactions occurring in the solutions. The viscosities are determined for these systems at various concentrations of donor-acceptor mixtures. Viscosity increases with concentration of aqueous electrolytes with serine confirms that increase of cohesive forces because of strong interaction [17]. Increase in viscosity with concentration in all the systems suggests that the extent of complexation increases with increase in concentration. Also from the Tables- 1 (water + NaCl +serine) &Table- 2(water+ MgCl 2 + serine), it is observed that viscosity of the solutions shows a non-linear behavior in both the systems. The order of variation of viscosity with increase in concentrations in the three systems is observed as follows; η water < η NaCl < η MgCl2 This supports the association of molecules of serine in aqueous MgCl 2 is more than serine in aqueous NaCl and pure water. Fig. 4. Plot of classical absorption factor (α/f 2 ) against mole fraction for the system (water +MgCl 2 +serine) at 2MH z and at K temperature Classical Absorption Factor (α/f 2 ) The values of classical absorption factor (α/f 2 ) for (water + NaCl+ serine) and (water+ MgCl 2 + serine) systems were calculated using Eq. (4). From Tables.1 & 2and Fig.3 and Fig.4, it is observed that the classical absorption factor (α/f 2 ) decreases with increase in concentrations. This is due to aggregation of solvent molecules of ions suggesting strong solute-solvent interaction. The graph for classical absorption factor (α/f 2 ) versus mole fraction (m) of (water+ NaCl+ serine) and (water+ MgCl 2 + serine) were plotted as shown in the Fig.3and Fig.4. The values of classical absorption factor (α/f 2 ) are

5 American Journal of Energy Science 2015; 2(4): maximum in water, moderate in aqueous NaCl and minimum in aqueous MgCl 2 Fig. 5. Plot of relaxation time (τ)) against mole fraction for the system (water +NaCl +serine) at 2MH z and at K temperature. Fig. 7. Plot of relaxation strength (r) against mole fraction for the system (water +NaCl +serine) at 2MH z and at K temperature. Fig. 6. Plot of relaxation time (τ) against mole fraction for the system (water +MgCl 2 +serine) at 2MH z and at K temperature Relaxation Time (τ) The values of relaxation time (τ) for (water + NaCl+ serine) and (water+ MgCl 2 + serine) systems were calculated using Eq. (5). From Tables.1 & 2, and Figs.5 &6, it is observed that the relaxation time (τ) decreases with increase in concentrations. This is due to aggregation of solvent molecules of ions suggesting strong solute-solvent interaction. The graph for relaxation time (τ) versus mole fraction (m) of (water + NaCl+ serine) and (water+ MgCl 2 + serine) was plotted as shown in the Fig.5and Fig.6. The values of relaxation time (τ) are maximum in water, moderate in aqueous NaCl and minimum in aqueous MgCl 2. Fig. 8. Plot of relaxation strength (r) against mole fraction for the system (water +MgCl 2 +serine) at 2MH z and at K temperature Relaxation Strength (r) The values of relaxation strength (r) for the systems (water + NaCl + serine) and (water+ MgCl 2 + serine) have been calculated using Equation (6). The experimental calculated data for different concentrations and temperature for both the systems have been presented in Tables.1 and 2. From Fig.7and Fig.8, it is clear that, in the present investigation, the relaxation strength (r) shows the increase and decrease non-linear behavior which indicates, there is significant interactions between the solutes and solvent. In present investigation positive values of relaxation strength (r)for some mole fractions confirms presence of strong molecular association in the system,while for negative values of relaxation strength (r) for some mole fractions indicate presence of weak interaction between molecules of the

6 113 Shilpa A. Mirikar and Govind K. Bichile: Thermodynamic and Interactions Studies of Serine with Aqueous Sodium Chloride at Different Concentrations, Constant Temperature and Constant Frequency at 2MH z compounds. The values of relaxation strength (r) are maximum in water, moderate in aqueous NaCl and minimum in aqueous MgCl 2 and vice - versa. The values of Rao s molar sound function (F) are maximum in water, moderate in aqueous MgCl 2 and minimum in aqueous NaCl. 4. Conclusion Fig. 9. Plot of Rao s molar sound function (F) against mole fraction for the system (water +NaCl +serine) at 2MH z and at K temperature. The ultrasonic velocity (u), density (ρ), viscosity (η) and other related parameters were calculated. The existence of type of molecular interactions in solute-solvent is favored in the systems, confirmed from the ultrasonic velocity (u), density (ρ), viscosity( η ) classical absorption factor (α/f 2 ), relaxation time (τ),relaxation strength (r) and Rao s molar sound function (F) data. Strong dispersive type intermolecular interactions are confirmed in the systems investigated. All the experimental determinations of acoustic parameters are strongly correlated. Ultrasonic velocity (u), density (ρ), viscosity (η) has been measured for serine in aqueous NaCl and MgCl 2 solution at K. The variation in ultrasonic velocity, density and viscosity and other related thermodynamic parameters such as classical absorption factor (α/f 2 ), relaxation time (τ),relaxation strength (r) and Rao s molar sound function (F), of serine at various concentrations and at constant temperature in both the NaCl based and MgCl 2 based systems, shows the non-linear increase or decrease behavior. The non linearity confirms the presence of solute-solvent, ion-ion, dipole-dipole, ion-solvent interactions. The observed molecular interaction, complex formation, hydrogen bond formation are responsible for the heteromolecular interaction in the liquid mixture. This provides useful information about inter and intra molecular interactions of liquid systems. The presence of ion ion, solute solvent (Amino acid, electrolyte and water) interactions is noticed in the mixed aqueous systems. References [1] Karuna Kumar D Bala, Rayapa K Reddy, G Srinivasa Rao, G.V Rama Rao and C Rambabu., J. Chem. Pharm. Res, 2011; 3(5); pp [2] G.V Ramarao, A.V Sarma and C Rambabu, Indian J. Pure Appl. Phys, 2004; 42; Fig. 10. Plot of Rao s molar sound function (F) against mole fraction for the system (water +MgCl 2 +serine) at 2MH z and at K temperature Rao s Molar Sound Function (F) Rao s molar sound function (F) for the systems (water +NaCl+ serine) and (water+ MgCl 2 + serine) have been computed using equation (7). The experimental computed values of Rao s molar sound function (F) are presented in Tables.1 and Table.2.It is observed that Rao s molar sound function (F) decreases with increase in concentrations and with increase in temperature. From Fig.9 and Fig. 10, it is clear that the values of F decrease as temperature increases [3] G.V Ramarao, A.V Sarma, D Ramachandran. And C Rambabu, Indian J. Pure Appl. Phys, 2005; 43; pp [4] G.V Ramarao, A.V Sarma, P.B Sandhyasri,C Rambabu C, Indian J. Pure Appl. Phys, 2007;45; pp [5] K Sreekanth, D.S Kumar, M Kondaiah and D Krishnarao, J.Chem.Pharm. Res, 2011; 3(4); pp [6] R Venis and R Rajkumar, J. Chem. Pharm. Res, 2011; 3(2); pp [7] S. A Mirikar, P. P Pawar, and G. K Bichile K, J. Chem. Pharm. Res, 2011;3(5) ; pp [8] T Ogawa, K Mizutani, M Yasuda, Dull. Chem. Soc. Japan, 1984; 51; pp2064.

7 American Journal of Energy Science 2015; 2(4): [9] R Bhatt, J.C Ahluwalia, J. Phys. Chem, 1995; 89; pp1099. [10] A Soto, A Arce, M.K Khoshkabarchi, Biophysics, Chem., 1998; 74; pp165. [11] C.C Chen, Y Zhuy, L.B Evans, Biotech prog, 19895(111); pp 198. [12] R.R Raposo, L.F Merida, M.A Esteso, J. Chem. Thermodyn, 1994; 26; pp1121. [14] D Das D and D.Khazra, Indian J. of Physical Chemistry, 2003; 77B (5); pp519. [15] T Ramanjipa, M.E Rao and E Rajgopal E, Indian J. of Pure & Appl. Physics, 1993; 31; pp 348. [16] A Pradhan, J.H Vera, Chem. Eng. Data, 2001; 45; pp140. [17] P.B Agrawal, Mohd Indrees Mohd Siddique. and M.L Narwade, Ind. J. Chem, 2003; 42A (5); pp1050. [13] M.K Khoshkbarchi, J.H Vera, AlCHE. J, 1996; 42; pp2354.

ISSN X Original Article ACOUSTICAL STUDIES OF BINARY LIQUID MIXTURES OF P-CHLOROTOLUENE IN CHLOROBENZENE AT DIFFERENT TEPERATURES

ISSN X Original Article ACOUSTICAL STUDIES OF BINARY LIQUID MIXTURES OF P-CHLOROTOLUENE IN CHLOROBENZENE AT DIFFERENT TEPERATURES Available online at http://www.urpjournals.com International Journal of Research in Pure and Applied Physics Universal Research Publications. All rights reserved ISSN 78-34 Original Article ACOUSTICAL