Jain, R. P.

Pandey, J. D.

English

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where v is the number of ions produced by thedissociation of one molecule, R is the gas constant,'( the mean molal activity coefficient of the solute,and m its molality. The heat of transport is theheat which must be removed from a region of solu-tion to which one mole of solute migrates in orderto maintain the temperature of that region constant.It is thus a measure of the interaction energy be-tween the solvated ions and their surroundings.Lacking any information on the activity coefficientsin our solutions, we computed the heat of transportfrom Eq. (3) assuming v = 3:.Q*= 3RPcr ... 3 )This approximation implies that(}In '(B= 1+ITnm(= 1.a condition which is fulfilled at infinite dilutionbut is not necessarily true at any other concentration.The heat of transfer, Q*, thus calculated is given.along with the value of D and cr in Table l.On interpreting heat of transfer as suggested-earlier", a higher value of heat of transport indi--cates low solvent-solute interaction energy. If thisis the situation, the solvent has a poor structure.-On comparing the values of heat of transport" for<CdIzin water, formamide (FM) and methylformamide(MFA), it is apparent that water is the best struc-tured solvent and tetramethylurea the poorestbecause the order of heat transport is as follows:QTMU>QilFA> QFM>Qii,oReferences1. TANNER, C. C., Trans. Faraday Sac .• 4,9 (1953), 611..2. CHAUN, J. & LENOBB, J., J. chim, Phys., 54 (1957), 872.3. TYRRELL, H. J. V .• FIRTH, J. G. & KENNEDY, M., J.chem . Soc., (1961), 3432.4. BIERLEIN, J. A., J. chem . Phys., 36 (1962), 2793.5. GUSTAFSSON, S. E., BECSEY, J. G. & BIERLEIN, J. A.,J.phys. Chem., 69 (1965), 1016.6. BRYNGDAHL, O. & LJUNGGREN, S., J. phys. Chem., 64(1960), 1264.7. BRYNGDAHL, 0., J. opt. Soc. Am., 53 (1963), 571.8. BECSEY, J. G., BIERLEIN, J. A. & GUSTAFSSON, S. E.,Z. Naturforsch, 210 (1966), 488.9. BLOKHRA, R. L., Electrochim, Acta, 17 (1972), 63.Corresponding Conductance in Aqueous &Non-aqueous MediaJ. D. PANDEY & R. P. JAINChemistry Department, University of AllahabadAllahabad 211002Received 22 July 1974; accepted 12 February 1975Conductance data in aqueous and non-aqueous mediaof 1 : 1 electrolytes have been analysed by the methodof corresponding conductance due to Guggenheim. The1:heoretical values of equivalent conductances at infinitedilutions •Ao ' have been obtained. The Walden producthas also been calculated on the basis of these results.GUGGENHEIMI developed a simple method ofanalysing conductivity data of 1: 1 electrolytesin aqueous solutions. In the present note Guggen-NOTESheim's corresponding conductance method has beenextended for the analysis of conductance data of1: 1 electrolytes in mixed solvents.Guggenheim's analysis of corresponding conduc-tance is based on Pitts2-4 equation (1) which contains. two adjustable parameters Ao' the molar conductanceat infinite dilution and a, the closest distance of a pairof ions for a completely dissociated 1: 1 electrolyte asA = Ao(1-0C1/21» -crc1/2'Y ... (1)In Eq. (1) 1> and 'Yare the unspecified functionsof c only and same for all completely dissociatedsalts, and 1>-?-1, 'Y-?-1 as c-?-O. The constants 0and cr are dependent on the nature of the solventand temperature. For two standard completelydissociated 1: 1 salts denoted by the subscripts 1and 2 having high and low values of A respectivelyGuggenheim derived the expression (2)A = AI -r(Al-A2) ... (2)Here, r is independent of concentration. Eq. (2)is known as the principle of corresponding con-ductance. In Eq. (2) there is only one adjustableparameter, r and the extrapolation of experimental A,A1 or A2 value is not required. Guggenheim- studiedthe behaviour of many 1: 1 salts, namely KCI, LiCl,NaCl, NH4Cl, KBr, KI, NaBrOs, LiClO<\;,NaCI04,Me4NC1, Me4NBr in aqueous media by the method ofcorresponding conductance and obtained good results.We have utilized the application of correspondingconductance for the study of 1: 1 electrolytes in non-aqueous media. The first set of study concerns withthe analysis of the conductances of CsCI04, LiCIO<\;,RbCI04, AgCI04, NH4Cl04, AgNOs in dimethyl-formamide. In the second set, we have studiedKCI04, LiCI04 and NaCl04 in aqueous media also .The experimental values of conductances ofLiCl04, RbCl04, CsCl04, AgCl04, NH4Cl04 andAgNOg in dimethylformamide (dielectric constant,D = 36·7) and KCl04, LiCI04 and NaCI04 in aqueousmedia at 25°C were taken from Prue-Sherringtonsand jones" work respectively, By selecting anythree of these salts, the single adjustable parameterr has been calculated. Different values of theore-tical conductances at corresponding constant con-centrations have been calculated by Eq. (2). Finally,the theoretical values of conductances at infinite dilu-tion Ao have been calculated by plotting theoreticalconductances against vc and extrapolating to zeroconcentration. It enables us to calculate the Waldenproduct, Ao1). The results are given in Tables 1-3.Table 2 shows the calculated values of molarconductances of C5Cl04, AgCI04 and NH4Cl04 indimethylforrnamide in the concentration range of0·0001 to 0·0010M. We have chosen two saltsLiCl04, RbCI04 as subscripts 1 and 2. The COD-TABLE 1 - CALCULATED VALUES OF CONDUCTANCES ATINFINITE DILUTION AND 'VALDEN PRODUCTElectrolyteCsCl04AgCI04NH4CI04AgN03KCl04Ao86·0587·2590·3181·35140·62Ao"IJ1·6281'6501'7081'5381'24759.................. "" _ ........... --.-- -----_ _-- -- .INDIAN J. CHEM., VOL. 14A, JANUARY 1976TABLE 2-CORRESPONDING CONDUCTANCESOF CsClO., AgClO., KH.ClO., AgNOs IN DIMETHYLFORMAMlDEAT25°C(ohm'+ cm-2 mole-l)Concentration (M)0·0001 0·0002 0·0003LiClO. (exp) 75·76 74·98 74'61RbClO. 82·71 82·08 81'80CsClO.* 84·67 84·13 83·90(84-6698) (84'0509) (83'5532)AgCIO. (expl] 85-83 85·02 84'548(85'8298) (85'2174) (84'97772)NH.ClO. 89·00 86·69(expH (88'9997) (88·4053) (88'2055)KJ (exp)KBrAgNOs (exp)§0·000479·6980'7477-06(77-0601)0·0006 0·0008 0·001073-69 72'6180'76 79·59(82'7226) (81'5276)83065(83'8842) (82-6744)(87'0586) (85'8084)78'4879·5970·67(75·7349)0·0015 0·001977·19 76·4377·1664·02(74-16)Calc. values in parentheses assuming *1'=1'2776; tr=1·4419; tr=1'8909; §1'=2·5047.TABLE 3 - CORRESPONDINGCONDUCTANCEOF KClO. IN AQUEOUSMEDIA AT 25°C (ohm:" cm-2 mole'<)Concentration (M)0·0005 0·001 0·002 0·005 0·010 0·020 0·050 0·070 0·100LiClO. (exp) 104'18 103·44 102·46 100·57 98·61 96·18 92·20 90·50 88'56NaClO. 115'64 114'87 113'80 111·75 109'59 106'96 102·40 100'52 98·43KClO. (exp)* 138·76 137·87 136·62 134-16 131-46 127·92 121-62 118·79 115'20(138'75) (137'92) (136'67) (134'30) (131,74) (128'64) (122-97) (120-73) 118·3417*Calculated values in parentheses assuming 1'=3·0174.ductance study of AgN03 in dimethylformamidehas been done in the concentration range of 0·0004 to0'0019M by choosing KI and KBr as the subscripts1 and 2. Finally theoretical values of conductancehave been calculated in the case of KCl04 (Table 3)in the cone. range of 0·0005 to 0·100M. The resultsare in good agreement with the experimental values.Theoretical values of 1\0 and Walden product 1\01)obtained for these salts are shown in Table 1.References1. GUGGENHEIM,E. A., Trans. Faraday Soc., 65 (1969), 2474.2. PITTS, E., Proc. R. Soc. Sec., A, 217 (1953), 43.3. PITTS, E., TABOR, B. E. & DALY, J., Trans. Faraday Soc .,65 (1970), 693.4. PITTS, E., TABOR, B. E. & DALY, J., Tmns. Faraday Soc.,66 (1969), 849.5. PRUE, J. E. & SHERRINGTON,P. J., Trans. Faraday Soc.,57 (1961), 1795.6. JONES, J. H., J. Am. chem , Soa., 67 (1945), 855.Studies on the Cell NiINi-Soap(s), K-Soap,Cu-Soap(s)\CuVVAHlDU. MALIK & AJAY K. JAINDepartment of Chemistry, University of Roorkee, RoorkeeReceived 9~Dece1nbey 1974; accepted 22 February 1975The e.m.f., temperature coefficient of e.m.f. and thethermodynamic parameters of the cell reaction havebeen computed for the cells of the type NiJNi-soap(s),K-soap, Cu-soap(s)!Cu. The soaps have been derivedfrom lauric, myristic, palmitic and stearic acids. Thecell's reactlon'[Is accompanied by decrease in enthalpyas well as entropy. The cell e.m.f. is also found to beindependent of concentration ofpotassium soap solution.fiOIN continuation of our earlier workl-5 on metal-metal soap electrode system, the e.m.f. of thecell of the type (A) has been evaluated.Ni'Ni-soapjs), K-soap, Cu-soap(sjC» (A)Potassium salts of lauric (C11), myristic (C13), pal-mitic (CIS) and stearic (C17) acids were preparedfrom reagent grade (BDH) acids and crystallizedfrom ethanol.Nickel and copper soaps were prepared by adirect metathesis reaction at 50-55° from the corres-ponding potassium soaps and aqueous solution ofnickel or coppe~ sulp?ate. The precipitated soapswere washed WIth distilled water and then withethanol to remove free precipitant. The soapsgave satisfactory elemental analysis.Nickel electrodes were prepared by depositingnickel on platinum wires by the electrolysis of asolution containing nickel sulphate (15%), boricacid (1%) and sodium chloride (0,6%). The elec-trodes were connected to a 4 V battery and a currentof 20 mamp was passed for about 2 hr. Copperelectrodes were prepared by depositing copper onplatinum wires by the electrolysis of a solutioncontaining CuS04 (8%) and H2S04 (4,6%). Theelectrodes were connected to a 2 V battery and acurrent of 15 mamp was passed for 4 hr.A Cambridge portable potentiometer was usedfor ~.m.f. measurements of the cell of the type (A)at different temperatures. The cell vessel employedwas of H type. The two limbs of the ceil wereprovided with nickel and copper electrodes. Thecell contained aqueous solution of potassium soapsaturated with nickel and copper soaps. Somesolid metal soaps were always added to the cell [tomake certain that potassium soap solution wassaturated with respect to metal soaps.IJ

Corresponding Conductance in Aqueous & Non-aqueous Media

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Corresponding Conductance in Aqueous & Non-aqueous Media

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