Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 2(10), 49-54, October (2012) Res.J.Chem. Sci. International Science Congress Association 49 Acoustical Properties and Surface Tension study of some Potassium salts in Polyacrylamide solution at 303K Ravichandran S. and Ramanathan K.Department of Physics, Sathyabama University, Chennai - 600119 Tamilnadu, INDIA 2*Department of Physics, Thiagarajar college of Engineering, Chennai - 600119 Tamilnadu, INDIAAvailable online at: www.isca.in Received 31st May 2012, revised 19th June 2012, accepted 6th July 2012Abstract Ultrasonic velocity and density of potassium nitrate, potassium iodide, potassium chloride and potassium hydroxide solution in polyacrylmaide binary solution has been measured at 303K in different concentration. Ultrasonic velocity has been measured using single frequency interferometer at 2 MHz (Model F-81). From the experimental data, other related thermodynamic parameters, viz adiabatic compressibility, intermolecular free length, acoustic impedance and surface tension are calculated. The compressibility of a solvent is higher than that of a solution and it decreases with the increase in concentration of the solution. The abrupt variation of a velocity indicates the formation of complex. The results have been discussed in terms of solute-solute and solute-solvent interactions between the component and the compatibility of these methods in predicting the interactions in these mistures has also been discussed. Keywords: Potassium salts with polyacrylamide-ultrasonic velocity-molecular interaction ultrasonic.Introduction In the recent years, there has been an increased interest in the physico-chemical properties of aqueous solution in polymer media1-3. In the recent years, it has been found that, the acoustical properties of solution have to be important parameters in the study of several chemical reactions and in the investigation of molecular inter actions. These Parameters are required to compute the internal pressure, free volume and other thermodynamic quantities. In many industrial applications, liquid mixtures rather than single component liquid system are used in processing and product formulations. Thermodynamic properties of liquid mixtures have been extensively used4-5 to study the departure of a real liquid mixture from ideality. The same authors have studied the ultrasonic velocity and densities in mixtures of polyacrylamide solution in sodium (meta) silicate and potassium silicate solutions in different concentrations at 303 K. The interaction of sodium dodecyl sulphate (SDS)/poly (vinyl Alcohol) (PVA) solution was studied by ultrasonic velocity measurements. The studies on ultrasonic parameters have become an emerging field in recent years. The objective of ultrasonic studies is to identify the molecular interaction between solute and solvent and to bring about the structural changes associated with them in terms of acoustic properties like sound velocity, adiabatic compressibility and acoustic impedance etc. Ultrasonic velocity, density, viscosity in mixtures of sodium dodecyl sulphate in polyvinyl alcohol was measured over the entire range of composition were studied by the same authors. The present paper deals with further studies carried out by the authors on the ultrasonic behavior of potassium salts in polyacrylamaide souton at different oncerations.Material and MethodsAR grade of Polyacrylamide (PAM) is used in the present study with a molecular weight of 5,000,000 g/mol. 5 gm of PAM were dissolved in 500 ml of distilled water to get a PAM solution of 1%. Highly purified quality of potassium nitrate, potassium iodide, potassium chloride and potassium hydroxide were dissolved in distilled water at low temperature to get 0.5 N. The potassium salt solution was added with PAM in different concentration like 10:90, 20:80, 30:70… and ultrasonic parameters were studied. The total volume of a solution should be maintained as 100 ml. For density measurements, the liquid mixtures were taken in a 10 ml gravity bottle (Borosil). The bottle was immersed in a water bath. In order to obtain a constant temperature, the specific gravity bottle was kept inside the water bath for about 30 minutes. Finally, the densities of the pure liquids and liquid mixtures wee measured using an electronic balance. The results of the densities are accurate to ± 0.5%. Ultrasonic interferometer of fixed frequency (2MHz) was used for measuring ultrasonic velocity. (F-81, Mittel Enter Prices, New Delhi). Density and ultrasonic velocity were measured for the different concentration of the mixed solution at 303K. Different acoustic parameters like adiabatic compressibility, acoustic impedance, intermolecular free length and surface tension were calculated at different concentration at 303K temperatures. A quartz crystal is fixed at the bottom of the cell, which when excited by RF source produces longitudinal ultrasonic waves of particular frequency which propagates in the medium. These waves are reflected at the metallic reflector, attached to a sensitive micrometer which can be moved up and Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(10), 49-54, October (2012) Res. J. Chem. Sci. International Science Congress Association 50 down. The incident and reflected waves form standing wave pattern. By moving the micrometer in the sample, maxima and minima are formed which can be observed in the micrometer of interferometer. These maxima are separated by half integral multiple of the wavelength of the ultrasonic wave. The densities at different temperatures were measured using 10ml specific gravity bottle and single pan macro balance. The uncertainty in density measurements was found to be 0.5kg/m3. These parameters are calculated by using standard relations. Results and DiscussionUltrasonic velocities of potassium salts solutions in polyacrylamide solution in different concentration at 303K have been determined and are presented in tables 1-4. Ultrasonic velocity varies in accordance with molecular interactions in solutions. The variation of ultrasonic velocity in a solution depends upon the intermolecular free length (L). The ultrasonic velocity increases whereas the free length decreases and vice versa. Presence of ion alters the intermolecular free length. Therefore, ultrasonic velocity of a binary solution will be different from that of the solvent. The minimum value of ultrasonic velocity indicates weakening of the molecular association at these concentrations. The variations of ultrasonic velocity with mole fraction of potassium salt solution at different concentrations are shown in Figure 1. It is observed that the ultrasonic velocity varies non-linearly with concentration and a sudden decrease at a particular concentration as reported earlier8-9. Density increases with increase in concentration ofpotassium salts in polyacrylamide solution, due to the presence of ions or particles. The variations in density with increase in concentration are shown in tables 1-4. When an ion is added to a solvent, it attracts certain solvent molecules towards itself by wrenching the molecular from bulk compressibility of a solvent is higher than that of a solution and it decreases with the increase in concentration of the solution. The deviation in adiabatic compressibility can be explained by taking into consideration of the following factor. i. Loss of di-polar association and difference in size and shape of the component molecules which leads to decrease in velocity and increase in compressibility. ii. Dipole-dipole interaction or hydrogen bonded complex formation between unlike molecules which lead to increase in sound velocity and decrease of compressibility. The actual deviation depends on the resultant effect. The observed decrease/increase in adiabatic compressibility, intermolecular free length, acoustic impedance and relative association with composition is an evidence of significant interaction between the component molecules in the binary mixtures. Adiabatic compressibility (ad) of the solution was calculated using the formula- ad)=1/(U)- (1) Where U is the ultrasonic velocity and is the density of the solution. The variation of adiabatic compressibility with the mole fraction for all the systems is shown in table 1-4. From the data, it is observed that adiabatic compressibility varies non-linearly with mole fraction of the salts solution. The variation of adiabatic compressibility of different potassium salts with polyacrylamide solution is shown in figure 2. In this present study, adiabatic compressibility is decreases with increase in the potassium salts which may be due to departure of solvent molecules around the ions. It means, insolvent interaction increases9-11. Acoustic impedance (Z) was calculated using the formula - (Z) = (U) (2) The acoustic impedance (Z) also shows the same trend of relative association. The variation of acoustic impedance with concentration is shown in figure 3. Acoustic impedance is almost reciprocal of adiabatic compressibility. In this present investigation, it is observed that these acoustic impedance (Z) value increase with increase in concentration of potassium salts in polyacrylamide solution. The linear variation of acoustic impedance with concentration confirms the presence ofmolecular association between the solute-solvent molecules. Such in increasing trends of impedance further support the possibility of molecular interaction between the solute-solvent molecules12,13. Intermolecular free length (L ) were calculated using the formula – (L ) = Kad (3) Where K is the Jacobson’s constant, ad is the adiabatic compressibility of the mixed solution. Intermolecular free length (Lf) decreases with the increase in concentration of thesolution. It may be stated that, density and free length are inversely related. The intermolecular free length is decrease with increase in concentration. The inter molecular freelength has an inverse behavior. The structural changes are also found to affect the variation of inter molecular free length. An increase in free length produces decrease in ultrasonic velocity. The variation of molecular free length of different potassium salts with polyacrylamide solution is shown in figure 3. The data shows that, the decrease of free length with the increase in concentration of potassium salts and reaches the minimum. The existence of minimum free length is anindication that the structural readjustment in the liquid mixture in the direction of les compressible phase or closer packing of molecules. Consequently the ultrasonic velocity increases. The sudden increase in free length with decrease in velocity at a high concentration of potassium nitrate and potassium iodide at a mole fraction of 0.6666 indicates that there is a significant interaction present between the solute molecules due to which structural arrangements of molecules are considerably affected14Surface tension () were calculated using the formula- Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(10), 49-54, October (2012) Res. J. Chem. Sci. International Science Congress Association 51 ) = (6.3×10-4) 3/2 (4) Where U is the ultrasonic velocity and is the density of the solution. Surface tension is used to study the surface composition of aqueous solution of the mixtures. A variation of surface tension shows the attractive interactions between the two solutions. The surface tension of a liquid mixture is not a simple function of the surface tension of the pure Liquids. At the interface, there is migration of the species having the lowest surface tension, or free energy per unit area, at the temperature of the system. This migration at the interface results in a liquid-phase rich in the component with the highest surface tension and a vapor phase rich in the component with the lowest surface tension. Surface tension increases with the addition of solute. The observation is in accordance with the change in mean free length15. The velocity, compressibility, impedance and molecular free length of all the systems are studied. Potassium nitrate and potassium iodide shows a non-linear variation with the concentration of solute. Further, the data have exhibited a dip in compressibility, there by indicating the complex formation. The effect of potassium nitrate on the ultrasonic velocity of polyacrylamide is illustrated in table 1. So there is oscillation with much non-linearity in the results, the general trend appears as an increase with increase in the potassium nitrate concentration. Hence the inter-chain interaction in polyacrylamide may be may be gradually suppressed with increase in the concentration of polyacrylamide. Since in polyacrylamide, there is dipole-dipole and Vander walls force of interaction. The former is more affected by potassium nitrate. In other words, the increase in the dielectric constant of the medium decreases the inter-chain interaction in polyacrylamide solution. The effect of potassium iodide on ultrasonic velocity of polyacrylamide is illustrated in table 2. There is a gradual decrease in velocity was noted within the mole fraction of potassium iodide. Hence potassium iodide might not enhance dielectric constant significantly in order to decrease the inter-chain interaction in polyacrylamide. Since there is a decrease, there must be enhancing interaction in polyacrylamide. The effect of mole fraction of potassium chloride inultrasonic velocity of polyacrylamide is illustrated in table 3. There is a gradual increase in ultrasonic velocity. Hence potassium chloride might significantly alter the dielectric constant of a medium and suppresses the inter-chain interaction in polyacrylamide solution. The effect of mole fraction of potassium hydroxide on velocity is illustrated in table 4. Here also, there is increase in velocity with mole fraction of potassium hydroxide is noted. From the above discussion it is evident that the inter-chain interaction in polyacrylamide is strongly influenced by the dielectric constant of the medium. Table-1Experimental values of ultrasonic velocity, density, adiabatic compressibility, acoustic impedance, molecular free length and surface tension of potassium nitrate in polyacrylamide solution Mole fraction of potassium nitrate Ultrasonic velocity (U)msDensity ( ) kgm-3Adiabatic compressibility ad)10-10kg-1msAcoustic impedance ( Z ) kgm-2-1Free length (L) 10-10m Surface Tension) Nm-1 0.0526 1519 1017 4.2591 1545326 0.8833 37948 0.1111 1524 1025 4.2010 1561686 0.8772 38412 0.1765 1522 1030 4.1891 1568066 0.8760 38545 0.2500 1532 1031 4.1366 1578431 0.8705 38916 0.3333 1530 1039 4.1131 1589168 0.8680 39160 0.4286 1528 1048 4.0854 1601909 0.8651 39449 0.5385 1539 1054 4.0073 1621405 0.8568 40074 0.6666 1522 1058 4.0818 1609584 0.8647 39562 0.8181 1541 1061 3.9718 1634333 0.8530 40413 1.0000 1554 1063 3.8975 1651078 0.8450 41005 Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(10), 49-54, October (2012) Res. J. Chem. Sci. International Science Congress Association 52 Table-2Experimental values of ultrasonic velocity, density, adiabatic compressibility, acoustic impedance, molecular free length and surface tension of potassium iodide in polyacrylamide solution Mole fraction of potassium iodide Ultrasonic velocity (U)msDensity )kgm-3Adiabatic compressibility ad) 10-10Kg-1msAcoustic impedance ( Z )kgm-2-1Molecular free length (L)1010m Surface Tension () Nm-1 0.0526 1516 1031 4.223 1562526 0.87953 38322 0.1111 1509 1039 4.225 1568300 0.87974 38383 0.1765 1504 1049 4.214 1578112 0.87855 38555 0.2500 1508 1058 4.156 1595449 0.87257 39032 0.3333 1505 1067 4.138 1606067 0.87063 39249 0.4286 1503 1075 4.117 1615569 0.86847 39463 0.5385 1504 1084 4.082 1629599 0.86467 39808 0.6666 1496 1092 4.091 1633851 0.86562 39817 0.8181 1498 1103 4.042 1651605 0.86047 40272 1.0000 1517 1012 4.293 1542148 0.88679 11974 Table-3Experimental values of ultrasonic velocity, density, adiabatic compressibility, acoustic impedance, molecular free length and surface tension of potassium chloride in polyacrylamide solution Mole fraction of potassium chloride Ultrasonic velocity (U)msDensity )kgm-3Adiabatic compressibility ad)10-10Kg-1msAcoustic impedance ( Z )kgm-2-1Molecular free length (L)1010m Surface Tension () Nm-1 0.0526 1523 1013 4.260 1541749 0.88339 37900 0.1111 1526 1018 4.218 1553382 0.87900 38233 0.1765 1530 1022 4.178 1563875 0.87488 38542 0.2500 1536 1025 4.133 1575163 0.87009 38894 0.3333 1539 1029 4.105 1582974 0.86712 39124 0.4286 1546 1032 4.055 1595255 0.86187 39515 0.5385 1549 1038 4.015 1607523 0.85763 39863 0.6666 1548 1040 4.011 1610185 0.85720 39915 0.8181 1555 1044 3.964 1622651 0.85211 40309 1.0000 1562 1049 3.925 1624502 0.84878 40525 Table 4 Experimental values of ultrasonic velocity, density, adiabatic compressibility, acoustic impedance, molecular free length and surface tension of potassium hydroxide in polyacrylamide solution Mole fraction of potassium hydroxide Ultrasonic velocity (U)msDensity )kgm-3Adiabatic compressibility ad)10-10kg-1msAcoustic impedance ( Z )kgm-2-1Molecular free length (L)1010m Surface tension )Nm-1 0.0526 1516 1014 4.288 1537837 0.88633 37727 0.1111 1523 1015 4.245 1546591 0.88185 38026 0.1765 1526 1016 4.227 1550390 0.87990 38157 0.2500 1534 1022 4.158 1567855 0.87273 38687 0.3333 1537 1025 4.131 1575194 0.86986 38905 0.4286 1548 1028 4.060 1591143 0.86239 39440 0.5385 1567 1031 3.951 1615366 0.85076 40282 0.6666 1572 1035 3.910 1626786 0.84629 40638 0.8181 1571 1043 3.888 1637507 0.84394 40885 1.0000 1574 1051 3.815 1645206 0.84021 41305 Research Journal of Chemical Sciences ____ _ Vol. 2(10), 49-54, October (2012) International Science Congress Association Graph between the variations of ultrasoni c Graph between the variations of adiabati c Graph between the variations of molec u Conclusion In this study, the measurement of ultrasonic velocity and other acoustical parameters of some potassium salts in polyacrylamide solution was studied in different concentrations at 303K. The experimental ultrasonic velocity data and other _ _____________________________________________ _ International Science Congress Association Figure-1 c velocity of various potassium Salts in polyacrylmaide concentrationsFigure-2 c compressibility of various Potassium salts in polyacr y different concentrationsFigure-3 u lar free length of various potassium Salts in polyacry lmai different concentrations In this study, the measurement of ultrasonic velocity and other acoustical parameters of some potassium salts in polyacrylamide solution was studied in different concentrations at 303K. The experimental ultrasonic velocity data and other acoust ical parameters contain valuable information regarding the solute- solvent interactions in the aqueous Based on our measurements, it can be concluded that the concentration of the potassium nitrate affects the dipole interaction and also affect the dielectric constant of the solution. The concentration of the potassium _ ________ ISSN 2231-606X Res. J. Chem. Sci. 53 b inary solution at different y lmaide binary solution at lmai de binary solution at ical parameters contain valuable information regarding solvent interactions in the aqueous solutions. Based on our measurements, it can be concluded that the concentration of the potassium nitrate affects the dipole -dipole and also affect the dielectric constant of the solution. The concentration of the potassium iodide decreases the inter- Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(10), 49-54, October (2012) Res. J. Chem. Sci. International Science Congress Association 54 chain interaction in the binary solution. In conclusion, the concentration, nature of the solvent, nature of the solute and its potion play an important role in determining the interactions occurring in the solutions. Similarly, potassium chloride and potassium hydroxide were also affecting the dielectric constant of a medium. These conclusions have given scope for further studies on the thermodynamic properties for the system. AcknowledgementThe authors thanks to Dr. Palanisamy, Professor, Department of Chemistry, Anna University, Chennai, Tamilnadu, Prof. A.N. Kanappan, Department of Physics, Annamalai University, and Dr. Chandramouleeswaran, Professor and Head (Rtd),Government of College of Engineering, Salem, Tamilnadu, India for their support in this work. References1.Ravichandran S. and Ramanathan K., Ultrasonic investigations of MSO, NSO4 and CSO4 aqueous in polyvinyl alcohol solution at 303K, Rasayan. J. Chem., , 375 (2010) 2.Syal Anita, Chauhan V.K. and Chauhan Suvarcha, Ultrasonic velocity, viscosity and density studies of poly (ethyleneglycols) (PEG - 8,000, PEG - 20,000) in acetonitrile (AN) and water (HO) mixtures at 250C, J. Pure. Appl.Ultrason. 27, 61 (2005)3.Pankaj K., Singh S.C. Bhatt, Investigation of Acoustical Parameters of Polyvinyl Acetate, App.Phy.Res., , 1 (2010)4.Krzysztof Bebek, Aleksandra Strugala., Acoustic and Thermodynamic properties of binary liquid mixtures of 2- Methyl-1-Propanol in hexane and cyclohexane at 293.15K., Mole. Quant. Acoust., 27, 337 (2006)5.Krzysztof Bebek, Speed of ultrasound and thermodynamic properties of 1-butanol in binary liquid mixtures at 293.15K., Mole. Quant. Acous., 26, 15 (2005) 6.Ravichandran S. and Ramanathan K., Acoustical parameters of polyacrylamide with sodium (meta) silicate and potassium silicate solution at 303 K., Polym. Chem.,1,698 (2010) 7.Ravichandran S. and Rathika Thaya Kumari C., Effect of Anionic Surfactant on the Thermo Acoustical Properties of Sodium Dodecyl Sulphate in Polyvinyl Alcohol Solution by Ultrasonic Method., E-J. Chem., 8, 77 (2011)8.Shanmuga Priya, Nithya, Velraj, Kanappan A.N., Molecular interactions studies in liquid mixture using Ultrasonic technique., Int. J. Adv. Sci. Tech., 18, 59 (2010)9.Anwar Ali, Anil Kumar Nain, Dinesh Chand and Rizwan Ahmad, Volumetric and Ultrasonic Studies of Molecular Interactions in Binary Mixtures of Dimethyl Sulfoxide with Some Aromatic Hydrocarbons at Different Temperatures, Bull.Chem. Soc. Jpn, 79, 702 (2006)10.Anwar Ali, Nabi F. and Tariq M., Volumetric, viscometric, ultrasonic, and refractive index properties of liquid mixtures of benzene with industrially important monomers at different temperatures, Int. J. Thermophy, 30, 464 (2009) 11.Anil Kumar Nain., Inversion of the Kirkwood-Buff theory of solutions: Application to tetrahydrofuran + aromatic hydrocarbon binary systems, J. Solut. Chem., 37, 1541 (2008)12.Nain A.K., Densities and volumetric properties of binary mixtures of aniline with 1- propanol, 2-propanol, 2methyl-1-propanol, 2-methyl-2-propanol at temperatures from 293.15 and 318.15 K., Int.J.Therm.Phys, 28, 1228 (2007)13.Anil Kumar Nain., Ultrasonic and viscometric studies of molecular interactions in binary mixtures of acetonitrile with some amides at different temperatures, Bull. Chem. Soc. Jpn, 79, 11, 1688 (2006)14.Ravichandran S. and Ramanathan K., Molecular Interactions with Polyacrylamide in Ethanolamine, Diethanolamine, and Triethanolamine Solutions Measured Ultrasonically, Poly. Plast. Tech Engg, 47, 169 (2008) 15.Ravichandran S. and Ramanathan K., Molecular interactions and Excess Thermodynamic properties of mixed solutions of Zinc sulphate and Zinc nitrate at 303K by Ultrasonic method, Int. J. App. Bio. Pharm. Tech., 1,705 (2010)