Bhatti, S S

Prabhakar, K P

Singh, D P

English

IACS Institutional Repository

In d ia n  J. P hys. 71A (5), 617-621 (1997)IJP A- an international journalUltrasonic investigations of the water, carbontetra- chloride and methanol ternary mixture at its miscibility pointK P Prabhakar, D P Singh* and S S Bhatti** Department of Physics, S V.S.D. College, Bhatoh-174 301, Himachal Pradesh, IndiaReceived 12 June. 1996, accepted 7 April 1997Abstract : Using experimentally measured ultrasound velocity and density data, an investigation in the ultrasound response of a ternary mixture (of water, carbontetrachloride and methanol) is done, at its miscibility point Several acoustical and thermodynamical parameters of the mixture are evaluated at 308 K. The physico-chemical behaviour of the ternary system is explained on the basis of obtained results.Keywords : Ultrasound velocity, thermodynamical parameters, miscibility point.PACS Nos. : 62.60,+v, 82 6Q.Lf, 43.35.BfThe non-linear behaviour of acoustical parameters in multicomponent liquid systems is related to the nature and strength of the interactions between molecules. To understand these interactions, some acoustical parameters have been used by different researchers [1-3]. These include molar sound velocity, molar adiabatic compressibility, acoustic impedance, free length, ralative association, free volume, available volume and'Van der Waals constant. Excess values of these parameters give an idea of the complex formation. All these parameters and their excess values are evaluated here for water-carbon tetrachloride-methanol ternary mixture at 308 K. The measured ultrasound velocity (u ) data (at 5 MHZ) and densities of the mixture reported by Krishnamoorthy e t a l [4,5] have been used in these calculations.The expressions for the various parameters, such as the adiabatic compressibility (K s) t molar sound velocity (/?), molar adiabatic compressibility (W), acoustic impedance (Z), intermolecular free lengths (f^ , thermodynamic approach; Z/, Jacobson's approach),Department of Physics, Shivalik College, Nay a Nongal-140 126, Punjab, India Department of Applied Physics, G.N.D. Univereity, Amritsar-143 005, Punjab, Jndia © 1997 I ACS618 K P Prabhakar, D P Singh and S S Bhattirelative association (R A ), available volume (Vfl), free volume (VJ) and van der Waals constant (b )f are taken from literature [6- 8]. The excess values of the acoustical and thermodynamical parameters (P) studied here are obtained from A P  = P am -  P m  = Pam ~  Z x iP j ^ N h e r z  A P  is excess value, P am is the experimental value and P im is the ideal mixture value of the parameter (P). Here, jc, and P, are the molar fraction and parameter (P)'s value for i-th component of the mixture.Table 1. Some acoustic parameters of fyOCxi) + CCI4U 2) + CH^OH(jr3) ternary mixture at 308 K (S.l. Units).X\ x2 u Vx 106 JfjXlO11 R x 106 Wx 106 z x i u r 3i bx 10®Pure Liquids \1.0000 0.0000 1469 18.12 46.62 206 390 146P 15.410.0000 1.0000 849 96.86 88.48 917 1907 1331 84.230.0000 0.0000 1051 40.75 115.18 414 771 826 34.60Top Layer0.7095 0.1327 1481 40 07 48.09 457 856 1404 34.610.6128 0.1146 1436 40.28 52.54 454 850 1325 34 720.4816 0.0901 1356 42.24 63.68 468 867 1158 34.290.3966 0.0742 1215 38.86 74 44 415 780 0 1106 33.22Bottom Layer0.7095 0.1327 850.6 24.40 88.77 226 478 1324 20 640.6128 0.1146 842.6 23.99 90.87 227 468 1306 20.280.4816 0.0901 853.3 24.41 92.92 231 475 1261 20.640.3966 0.0742 866.0 22.89 86.30 218 450 1338 19.35Ternary Mixture0.4160 0.0255 1294 32.27 65.88 352 661 1173 27.550.3639 0.0401 1215 34.97 73.65 373 705 1118 29.840.3000 0.0551 1116 36.68 85.53 380 724 1048 31.250.2655 0.0813 1078 39.00 88.22 400 767 1051 33.240.2158 0,1189 1065 42.50 86.61 434 838 1081 36.281= 1 .0 0 0 -1 1*1 +* 2)Table 2. Some acoustic and thermodynamic parameters of H2OU1 ) + CCI^j^ ) + CH3OFKX3)mixture at 308 K (S.l. Units).*\ x2 Vq x IO6 VeFx 106 LfX 10 12 Vf x 1012 R.A. AVfX I06 AVaxl(fi ALfX !0 12Pure Liquids1.0000 0.0000 14.92 3.19 25.59 43.40 4.88 2.71Q.000Q 1.0000 76.04 20.81 56.28 59.75> 1.20 12.620.0000 0.0000 30.93 <9.81 48.40 68.21 2.80 6.15Ultrasonic investigations o f  the water, carbontetmchloride etc 619Table 2 . {Cant'd.)*1 *2 V'o x io 6 v;jX lO 6 LfX 1 0 12 L ’j  x 10 12 R.A. AVfX 106 AV0 x  I06 ALfX 1012Top Layer0.7095 0.1327 25.56 14.51 84.24 44.08 0.16 5.47 7.93 47.460.6128 0.1146 26.30 13.98 76.84 46.07 0.21 5.56 6.97 41.060.4816 0.0901 27.29 14.95 80.17 50.72 0.25 5.95 7.34 41.580.3966 0.0742 27.93 10.93 57.67 54.84 0.86 5.64 2.92 17.54Bottom Layer0.7095 0.1327 15.57 8.83 68.78 59-89 0.66 3.76 2.25 43.340.6128 0.1146 15.31 8.68 68.40 60.59 0.70 3.70 1.66 36.230.4816 0.0901 15.58 7.31 54.94 61.27 1.25 3.77 -0.31 21.560.3966 0.0742 14.61 8.28 67.34 59.05 0.67 3.53 0.28 1.89Ternary Mixture0.4160 0.0255 25.43 6.84 38.47 51.59 2.41 4.72 -0.49 3.460.3639 0.0401 27.33 7.63 40.88 54.55 3.12 5.13 -0.34 3.400.3000 0.0551 28.63 8.06 41.84 58.78 2.77 5.44 -0.38 2.790.2655 0.0813 30.34 8.66 43.24 59.70 2.63 5.76 -0.29 2.880.2158 0.1189 32.85 9.64 45.69 59.15 2.17 6.21 -0.05 3.36*3 = 1 .0 0 0 -  (rj + * 2)Table 3. Some excess parameters of H2OU1 ) + CCI4U 2 ) (S.l. Units).+ CH3OHU3 ) mixture at 308 K*1 x2 Au M AV x 10^ AKs x  1011 A R x  106 AW x  106 AZx  HT3Top Layer0.7095 0.1327 160.2 -89.37 7.93 -14.90 123 207 60.950.6128 0.1146 152.0 -80.12 6.97 -17.56 110 185 52.830.4816 0.0901 121.9 -102.63 7.34 -16.07 108 180 -18.940.3966 0.0742 13.2 -16.52 2.92 -11,56 46 78 -9,43Bottom Layer0.7095 0.1327 -470.2 519.6 -7.74 25.78 -107 -171 -18.650.6128 0.1146 -441.4 546.9 -9.33 20.77 -118 -197 33.430.4816 0.0901 -380.8 521.4 -10.50 13.17 -127 -213 84.210.3966 0.0742 -335.8 618.5 -13.05 0.30 -151 -252 222.89Ternary Layer0.4160 0.0255 74.26 14.03 -0.49 -20.09 11 20 79.260.3639 0.0401 5.91 16.21 -0.34 -17.06 9 17 24.400.3000 0.0551 -49.58 46.97 -0.37 -7.64 , 1 5 3.190.2655 0.0813 -67.35 76.89 -0.29 -6.56 0 4 16.140.2158 0.1189 -52.50 93.90 -0.05 -10.64 5 13 60.93*3 = 1.000 — | *+*2)620 K P Prabhakar, D P Singh and S S BhattiThe results Obtained (in S.I. units) for the ternary mixture under study, are presented in Tables 1 to 3. In this system, water (H20 ) and carbontetrachloride (CC14) are the two immiscible components and methanol (which is freely miscible with each of them) is the third component. It is expected that the added methanol (CH3OH) will distribute between water and carbon-tetrachloridc. But, it is noted that as more and more methanol is added more CC14 is being extracted into the top layer, as is obvious from decreasing values of u (Table 1, column 3). An examination of the bottom layer, indicates the presence of a single component (CC14), irrespective of the amount of methanol added. This is indicated by almost constant u values for the bottom layer (Table 1 , column 3). The added third component seems to modify the properties of only one layer (top layer) and the binary mixture extracts the second immiscible layer (bottom layer) into it. jIt is interesting to note for tl^ e ternary system that as the mole fraction x 2 of the CC14 increases, the quantity of the methanol (i.e. jc3) required for homogenizing the layers, also increases till it reaches a maximum for a similar (i .e . maximum) mole fraction of the CC14. It is found that as x { (mole fraction .of H20 ) is decreased such that x 2 is increased, the u decreases (Table 1 , column 3) and the K s (Table 1, column 5) increases. This is likely due to the replacement of highly associated H20  molecules (Dipole moment = 1.87 D) by unassociated molecules of CCl4 (Dipole moment = ODj and less associated molecules of CH3OH (Dipole moment = 1.70 D). The V, R, W, Z  and b values vary erratically with rise in jc3 in the top layer ('Jable 1 ), .whereas these parameters report an almost constant behaviour with such a change in bottom layer. In the ternary system, there is a regular increase in the values of V, K, R, W  and b , with rise in x3. However, behaviour of Z is opposite to that reported for V  and K s etc. for this system. This trend of variation of the acoustical parameters can be understood as follows.Composition changes (with addition of large sized molecules of CC14 and CH3OH, as compared to H20  molecules) in a ternary system, enhances the dispersion forces in it, leading to an increase in its molar volume (10 The increase in V  affects the K s, R and W. The presence of strongly hydrogen bonded molecules of H20  and CHjOH contributes to attractive interactions in the system. In the ternary system, V j  and Vf show a steady increase in their values with rise in CC14 contents. While these parameters report an almost constant behaviour for bottom layer, their variation for top layer is erratic (Table 2). In the present ternary mixture, the relative association (RA) is found to be high (around 2.8) as compared to RA values for top and bottom layers. It points to the dominance of attractive interactions over the dispersive forces in the ternary system, as compared to the magnitude of such forces in the top and bottom layers. For the ternary mixture, the rise in x 2 causes expansion, increasing V, K s, b , Va, Lf and L'jThe Lf and L' increase due to looser packing of molecules. Obviously, the intermolecular cohesion present in the system weakens with rise in content of CC14. This trend is confirmed by the slight decrease reported in RA values for the system (Table 2). As a measure of van der Waals interactions in the system, the co-volume 'b' is determined.Ultrasonic investigations o f the water, carbontetrachloride etc 621It registers a steady rise from 27.55 x 10-4 to 36.28 x lO^mVmole for the mixture whereas it reports an almost constant behaviour for top layer and bottom layer of the mixture (Table 1).The molecules in a solution interact with each other to form new complex species making the solution non-ideal. The negative deviations from ideality of K s, in the binary/ternary mixtures are mainly due to formation of complexes and molecular association by weak bonds [8-10]. However, if the deviations are positive, they may be attributed to molecular dissociation of an associated species caused by addition of a component leading to weak interactions mainly due to dispersion forces [10].Excess molar volume (4V), excess available volume (4 Vfl), excess adiabatic compressibility (AK S) are negative over the entire range of compositions investigated for the ternary system. Excess density (A d) and (A K S) show a similar change for top layer, while excess molar sound velocity (A R ), excess molar adiabatic compressibility (4W), excess ultrasound velocity (A u) and (AV) show a similar variation for bottom layer (Table 3). From Tables 2 and 3, it is obvious that for the ternary mixture, the additivity rule is obeyed in case of Va, Lf, V, R  and W in a better way than in case with K s, whereas this is not so in case of top layer and bottom layer mixtures. However, the analysis of the trend of variations of excess parameters points to the existence of only weak interactions (of the van der Wadis type) due to the presence of non-polar CCI4 molecules in the bottom layer, whereas relatively stronger attractive interactions exist due to the presence of hydrogen bonded molecules of H20  and CH3OH in the top layer. The behaviour of the ternary mixture H20-CC14-CHjOH is intermediate of the two extremes, in general. It is pointed out that for H20  + CCI4 inhomogeneous mixture, on addition of the methanol, there is a progressive variation in the acoustic and thermodynamic response of the two layers, due to the distribution of the third component between them.References[ 1J A N  Kannappan and V Rajendran Indian J. Pure Appi Phys. 30 240 ( 1992)[2] D P Singh. A P Singh and S S Bhatti J. Pure Appi UUrason 11 62 (1989)[3] S S Bhatti and D P Singh J. Pure and Appi. Ultrason 6 5 (1984)[4] K Krishnamoorthy, S O Pillai and J Kuppusami Indian J. pure Appi Phys 11 677 (1973)[5] K Krishnamoorthy. J Kuppusami and S 0  Pillai Curr. Sci. 44 8 (1975)[6] D P Singh and A P Singh J. Acoust. Soc. Am. 15 3220 (1993)[7] D P Singh. M Lai and B Singh Acoust. Lett. 15 235 (1992)18] D P  Singh PhD Thesis (G.N.D. University, Amritsar, India) (1985)|9] R J Fort and W R Moore Trans. Farad. Soc. 61 2102 (1965)[10] D P Singh and S C Kalsh Acoust. Lett. 14 206 (1991)

Ultrasonic Investigations of the Water, Carbontetrachloride and Methanol Ternary Mixtures at its Miscibility Point

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Ultrasonic Investigations of the Water, Carbontetrachloride and Methanol Ternary Mixtures at its Miscibility Point

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