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Indian Journal of CltemistryVol. 17A, April 1979, pp. 352-354

Physicochemical Studies in Non-aqueous Solvents: Part XVI-Conductance Studies of Some I: I Electrolytes in Sulpholane

S. P. NARULA*t. G. DELLESAL~E, M. WARTEL.& Y. ADGERLaboratoire Chimie Minerale-l , Universite des Sciences et Technique de Lille-I , 59650 Villeneuve D'Ascq. (France),

andS. P. JAUHAR

Department of Chemistry, Panjab University, Chandigarh 160014

Received 15 June 1978; revised 11 August 1978; accepted 8 September 1978

Conductances of tetraethylammonium, tetraphenylarsonium and pyridinium chlorosulphates,tetraethylammoniumhydro~en sulphate, sodium acetosulphate, tetraphenylphosphonium chloride,tetrame thylamrnorrlum, tetrabutylamrnonium, tetrapnenylphosphonhrm arid tetraphenylarsoniumirnidobis(sulphuryl chlorides), Le. R.M[N(S02C1)2]' tetraethylammonium and silver perchlorateshave been measured in the concentration range 6·7-93·9 x 10-4M in sulpholane at 30°. Limitingequivalent conductances (Ao) and association constants (KA) of these salts have been obtainedfrom Fuoss-Onsa~er-Skinner equation as well as from Fuoss-Hsia equation expanded byFernandez-Prini and compared. The data from both the equations are in fair agreement witheach other. Limiting conductances of various ions have been calculated using the availabletransference number data and are found to decrease in the order: Ag+>PyH+>Et.N+>Ph.As+>Ph.P+>n-Bu.N+ and CI->ClO.>SOsCI->CHsCOOSO;> [N(S02CI)2]->HSO •.

THOUGH considerable conductance data oncommon electrolytes in nonaqueous medial areavailable, no serious attempt seems to have

been made to collect such data for relativelyuncommon salts and consequently, approximationsare resorted to interpret the behaviour of these saltsin solution. Tetraphenylarsonium and pyridiniumchlorosulphates, tetraethylammoniumhydrogen .sul-phate, sodium acetosulphate, tetraphenylphospho~lUmchloride, tetraethylammonium, tetrabutylammom~m,tetraphenylphosphonium and tetraphenylarsoniumimidobis(sulphuryl chlorides), i.e. R4M[N(S02Cl)2Jare obtainable in state of good purity and areappreciably soluble in sulpholane (tetrahydr?thio-phene 1,l-dioxide) at 30°. Conductance studies ofthese salts have now been undertaken in this solventwith a view to throwing light on the solute-solventinteractions. The data have also been analysedby the recent conductance equations.

Materials and MethodsFreshly distilled sulpholane (E. Merck), purified

by the reported methods, was used for each experi-mental run and its physical constants (sp. cond.,2-5 X 10-8 ohrrr ' crrr+; density, 1·2623 g ml-l andviscosity, 10·29 X 10-2p; all at 30°) were checkedbefore use. The water contents in these runs wereless than 10 ppm (Karl Fischer technique).

Silv.er and tetraethylammonium perchlorates" andsodium acetosulphate+ and all the other salts" wereprepared and/or purified by the existing methods.

tPresent address: Department of Chemistry, PanjabUniversity, Chandigarh 160014.

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The apparatus and procedure for conductance-measurements were essentially the same as reported.before".

Results and DiscussionConductance studies - Conductances of various.

electrolytes have been measured in the concentrationrange 6·7-93·9 X 10-4M and the plots of equivalentconductance versus square root of concentration are··given in Figs. 1 and 2.

The conductance data have been analysed by theFuoss-Onsager-Skinner (FOS) equationsf both forassociated (Eq. 1) and dissociated (Eq. 2) electro-lytes.

A = Ao-S(CY)1/2+E'CYln(6E~CY)+LCY-KA CYf2... (1)

A = AO-SCl/2+E'C In (6EiC) + (L-AAo)C ... (2)

The symbols have their usual meanings; 5 =a;Ao+~, E = E~Ao-E2 and the various constants«, ~, Ei and Ez as obtained from the physicalproperties of the solvent are 0·5439,6·996, 1·300 and2·443 respectively. The parameters Ao, Land K(for associated electrolytes) have been determined.by the least square computor programme followingthe algorithm given by Fuoss et al»,

The analysis of the conductance data in termsof Eq. (1) reveals that the association constantsfor tetraphenylphosphonium chloride, tetraphenyl-arsonium imidobis(sulphuryl chloride), tetraphenyl-arsonium chlorosulphate and sodium acetosulphateare positive, but negative for the other salts.Further, the association constants for the first two-

NARULA et al.: CONDUCTANCES OF 1: 1 ELECTROLYTES IN SULPHOLANE

salts are less than ten: Fuoss ct al.6 have suggestedthe use of Eq. (2) for the salts having associationconstants less than 10. Thus, the conductance dataof the two electrolytes along with those which givenegative association constants have further beenanalysed by Eq. (2). All the relevant data alon-gwith standard deviations of the various parametersare recorded in Table 1.

The conductance data have also been treated using'Fuoss-Hsia-Fernandez-Prini (FHFP) Eqs. (3-5), ob-Jained by expandingtr? the Fuoss-Hsia expression-",where tile symbols have the usual meanings.A = Y[Ao-S(CY)1/2+ECY log CY+ JCY + J3/2 (6Y)3/2]

... (3)

... (4)1-Y

KA = Y2Cf!

-A (CY)1/2 'In!± = 1+BR(CY)1/2 ... (5)

A.

HPYS03CI

10'0'A

~ Et4N[NCS02CIJ2]w 8'0' Et HSO AUz

Ph4N[Ncs02CIJ21 A«~u A=>a 6'0' Bz0 10'0'uI-

4'0 ~zw

Ph4AS[NCS02CI)2]..J8'0'~

=> 2·0aU4N[NCS02CIJ21~?

0w

6'0'

0'0' 0"0'2 0"0'4 0"0'6 00'6 0'-10 0'-12

SQUARE ROO. OF CONCENTRATION Crc )Fig. 1 - Plots of equivalent conductance versus squareroot of concentration for various electrolytes in sulpholane

at 300

'The distance parameters in Eq. (5), J and J3/2 havebeen taken as equal t09,10 Bjerrum's critical distance,q = z2e2j2DkT. The expressions for; J and J3/2.used here are those given by Fernandez-Prini".Under these conditions, conductance depends upontwo parameters A and KA which are adjusted bya least square method to fit the experimental data.The values of Ao and KA obtained by this methodare also reported in Table 1. It is apparent thatfor the electrolytes used here, Ao and KA valuesdiffer only slightly by the two methods.

Single ion conductances - From limiting equivalentconductance (Ao)of tetraethylammonium perchloratereported here and the limiting conductance ofC104 ion derived from available experimental trans-ference number data--, the conductance of Et4N ion+has been found to be 4·01 ohm-1 cm2 mol->. This.

12·0P"4PCI

AqCI04

~IO'O (14 NSO'3C1<--" PI>..• 4ASS03CIuZ 8·0'••~u::laz0' 60u~Z\oJ..Js 40:;cr...

20

0-00 0-02 0-04 0-06 0-06 0·10 0-12

SQUARE ROOT OF CONCENTRATIO'N (JC)

Fig. 2 - Plots of equivalent conductance versus squareroot of concentration for various electrolytes in sulpholane

at 300

TABLE 1 - CONDUCTANCE PARAMETERS OF SOME 1: 1 ELECTROLYTES IN SULPHOLANE AT 300

Electrolyte FOS FHFP

Ao KA (fA Ao KA (fA

Ph.PCI 12·37±0'02* 6'2±2'3 0·01 12·33±0·01 6'0±0'02 0'0112-32±0'01 t 0'01

Ph.P[N (S02Cl)2J 7·70±0·01 0·01 7'70±0'01 4'5±0'02 0·01Ph.As[N(SO.CI)2J 7'93±0'03* 8'6±6'7 0'03 7'91±0'02 7'3±0'04 0·01

7'90±0'01 t 0·02Et.N[N(S02CI)2J _8·72±0·01 0·01 8·69±0·01 0·4±0·02 0'01Bu.N[N(S02Cl) 21 7·46±0·01 0·01 7'45 ±0'01 " 3'1 ±0'2 0·01Et.NSO.CI 10·52±0·0l 0·01 10'52±0'02 4'6±0'6 0·01Ph.AsSO.CI 9-68±0'06 13·6±7·9 0·05 9·61±0'01 9'5±0'5 0'01HPySO.CI 10·57±0·01 0'02 10'S6±0'01 2·S±0·4 0·02CH.COOS03Na 8·61±0'06 2S0±21 0·02 8'S3±0'02 23·0±3·0 0'01Et.NHSO. 8'10±0'02 0'02 8'09±0'02 4'6±0'8 0·02tEt.NCIO. 10·67±0'01 * 0·01 10'70±0'01 10·1±0'3 0·01AgCIO. 11·64±0·07 14'2± 7-8 0·06 l1'S4±0'01 9·4±0·4 0'01

*Using Eq. (1).[Using Eq. (2). -,tValue is in fair agreement with that given in ref. 12.

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INDIAN J. CHEM., VOL. 17A, APRIL 1979

TABLE 2 - LIMITING IONIC CONDUCTANCESOFVARIOUS UNIVALENT IONS IN SULPHOLANEAT 30°C

Ion AU Ion A~+

Me4N+ 4'31* CI- 9'31 (9'30)*Et,N+ 4·01 (3-98)* SOaCI- 6'45tPr4N+ 3'23* SOaCHaCOO- 4'92Bu4N+ 2'77 (2-80)* HSO, 4'08Ph,P+ 3·02 [N(SO:Cl) 2]- 4'68Ph2As+ 3'23 cio; 6'69*Py+H 4·11Ag+ 4-85Na+ 3'61*

*Values from refs. 11, 12.[Mean of the two values ±0'06A units.

value .is i.in, fair .agreement with the reportedvaluesll•12. The limiting ionic conductances ofEt"N+, Na" and CIO, ionsll have then been usedto compute )..~ values for different electrolytesemploying Kohlrausch's law. The values are record-ed in Table 2.

The magnitude_of ionic mobilities for cations andanions followtile order: Ag+>Me4N+>PyH+>Et4N+>n-Pr"N+>Ph4As+>Ph4P+>n-Bu"N+ and CI~>CI04> S03CI-> CH3COOSO;> [N(S02CI)21->HSO,. •

The data in Table 2 show that the, mobilitiesof the ions decrease with increase in size of the

354

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.ions, However, Ph"P+ and HS04 ions are exceptionsto this generalization. The value for HSO, ionsmay be explained through slight solvation effect(probably through hydrogen bonding); neverthelessthe lower' mobility of Ph4P+ ion than that ofPh"As+ is unexpected. A similar behaviour has also 'been observed in the case of nitromethanes.

References.'1. FERNANDEZ-PRINI, R. Physical chemistry of organic

solvent systems Ch. 5 Part 1 edited by A. K. Covingtonand T. Dickinscn (Plenum Press, New York), 1973.525. '

2. PIERENS, P., AUGER, Y., FISCHER, J. C. &WAIiTEL, M:,Can. J. Chem., 53 (1975), 2989. '

3. PAUL, R. C., BANAlT, J. S. & NARULA, S. P., Z. phys.Chern, (N.F.), 94 (1975), 199. ' "

4. PESKI, V., Rec. Trav. Cbim., 40 (1921), 103.5. HEUBEL, J., FISCHER, J. C., DELLESALLE, G., NARULA,

S. P., PAUL, R. C., JAUHAR, S. P. & BANAIT, J. S.,Indian J. Chem., 15A (1977), 687.,

6. Fuoss, R. M., ONSAGER, L. & SKINNER, J. F., J. phys.Chem., 69 (1965), 2581.

7. FERENANDEZ-PRINI, R., Trans. Faraday Soc., 65 (1969),3311.

8. JUSTICE, J. C., BURY, R. & TREINER, C., J: chim: Phys.et, Biol, (FI'.!fnce), 65 (1968), 1708. - .

9. JusTrcE~ J. C., J. cbim, Phys. et. BioI. (l'rance), 06\1969), 1193. - -

10. Fuoss, R. M. & HSIA. K; L., Proc. nat; A cad, Sci,U.S.A., 57 (1967), 1550; 58 (1968),1818. .

11. DELLA-MoNlCA, M., LAMANNA, U. & SENATORE, L.,r-pkys, Chem., 72 (1968), 2124. .,

12. D~LLA-MoNICA, M. & LAMANNA, U., J. ,phYs. ·Chein ••.72 (1968), 4329.

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