2222 CAN;lDI.&N JOURXAL O F CI-IEMISTRY. VOL. 44, l O G G

6. Y. POCICER. J. Che111. Soc. 1292 (1960). 7. R. L. STRONG. J. Am. Chem. Soc. 87, 3563 (1965). S. D. P. STEVENSON and D. 0. SCHISSLE~. In The chemical and biolorrical actio~i of radiations. 1-01, V.

Edited by M. Haissinsky. Academic Press, London. 1961. p. 258. -

9. FFRANCON W~LL~AMS. Quart. Rev. 17, 101 (1963). 10. F. W. LAMPE. J. Phys. Chern. 63, 1986 (1959). 11. 11. C. Rvafr;EL~r and D. A. AR~ISTROYG. Can. J. Chem. 41, 1104 (1963).

MULTICOMPONENT DIFFUSION IN THE 85Kr-SO?-Kr SYSTERI

Curtiss and I-Iirschfelder ( I ) have shown that the n~ulticomponent difiusion coefficient Dii can be written to a first approximation as

IKI is the determinant of I<,, and K i i are the minors. If, however, one component 'i' is present in trace quantity, then its diffusion coefficient Di,,,, is given by (2 )

1 PI I 5 = C ---

(Di+mix)l j+i (aijll '

\\;here x j is the mole fraction of the jth component and is the usual binary diffusion coefficient. For a three-component system eq. [2] becoines

and hence to a first approxinlation:

The plot of I/D,,,, vs. x3 will be a straight line whose intercepts on the ordinate a t x3 = 0 and .x3 = 1 give the values of 9 1 2 and 9 1 3 . Applying the mass correction, 11-e get the usual Bz2 and Z D Z 3 values.

Several experiments (3-6) confirm that eq. [4] holds quite accurately. I-Iowever, \Yatts (7) in a recent paper on the nlulticoinponent diffusion of 133Xe in binary mixtures of S e with other inert gases has observed a departure froin eq. [4]. In the present investigation 11-e have measured the diffusion coefficient of radioactive a51<r in binary mixtures of normal l~rypton and SO? to test further the validity of eq. [4].

EXPERIMENTAL RESULTS

The apparatus employed in the present investigation is a two-chamber apparatus of the Ney and Arinistead (8) type. The apparatus and the experinlental procedures have been fully described by Srivastava and Paul ( 3 ) . Pure dry SO? gas was prepared by a method

Canadian Journal of Chemistry. Volume 44 (19GG)

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NOTES 2223

described in detail by Srivastava and Saran (9). The thermostatic bath temperature was maintained constant a t 30 OC xvithin &0.05 OC by a Sunvic electronic relay. The analysis was done by a scintillation counter.

'I--XBLE I

D c n l c d (cinL/s) Composition Pressure D m , t

of SO:! in mm Hg (cmvs) a* b * C*

0.0000 30.70 0 1018 0.1015 0 1008 0.1008 0 2556 32.88 0 0970 0.0972 0.0966 0 0955 0.4959 25 53 0.0932 0.0932 0 0929 0.0909 0.7343 22.19 0.0894 0.0896 0.0896 0.0865 1,0000 30.54 0 0859 0.0859 0.0861 0 0527

" (a ) Utilizing the experimental values of D o x p t at x = 0 and x = 1 and using eq. [ 4 ] ( 6 ) utilizing the unlike force parameters for the Kr-SO? system from observed binary diffusion coefficients (9) hnd eq. [A]; (c) utilizing the force parameters for SOz from viscosity (10) and the combination rules for polar-nonpolar interaction and eq. [3] .

The experimental values of the diffusion coefficient for various concentrations of SO? are given in Table I. The D,,,, values recorded in column 3 \Irere obtained by reduction t o atmospheric pressure. We believe that our data are correct within &l%.

DISCUSSION

The values of DcnIcd in column 4 have been obtained by using the D,,,, values for 0 and 100yo SO? and eq. [4] to calculate the composition dependence of D,,,,. I t can be seen that the agreement between the two sets is quite satisfactory. The values of DCnlcd in column 5 have been obtained by utilizing the unlike interaction parameters for the I<r-SO2 system from observed binary diffusion coefficients (9) and applying the mass correction. The agreement with the observed values is quite satisfactory. Column 6 gives the values of Dcnlcd obtained by utilizing the force constants of SO2 from viscosity (10) in the combining rules for unlike force parameters and applying the mass correction. The calculated values of diffusion coefficients are somewhat smaller than the observed values. This is due to the smaller values of the binary diffusion coefficient obtained from the force constants of SOz fro111 viscosity. The possible sources of discrepancy between the values of binary diffusion coefficients obtained from viscosity and those observed have been discussed elsewhere (9). After application of the Inass correction, the values of D13 and D12 from Table I become 0.OS62 and 0.102 respectively. These values compare quite well with the values 9 Z 3 = 0.0564 a t 30 OC (9) and 3 3 2 2 = 0.1035 a t 31.5 OC (3).

The authors are grateful to Prof. B. N. Srivastava for his keen interest and valuable guidance.

1. C. F. CURTISS and J. 0 . HIRSCHFLLDER. J. Chem. Phys. 17, 550 (1049). 2. 1. 0 . HIRSCHFELDE~~ and C. F. CURTISS. Symposi~~m on Combustiorl, 3rd, RIadison, \vis., 1948. 1949.

~ ~

p. 124. 3. B. N. SILIVASTAVA and R. PAUL. Physica, 28, 646 (1962). 4. R. PAUL. Indian J. Phys. 36, 464 (1962). 5. L. MILLER and P. C. CABMAN. Trans. Faradav Soc. 57. 2143 11961): 60. 33 11964). , , \

6. H. WATTS. Trans. Faraday Soc. 60, 1745 (1964). 7. H. WATTS. Carl. J. Chern. 43, 431 (1965). S. E. P. NEY and F. C. ARIIISTEAD. Phys. Rev. 71, 14 (1947). 9. B. N. SILIVASTAVA and A. SARAN. Can. J. Phys. To be published.

10. L. MONCHICR and E. A. ~IASON. J. Chein. Phys. 35, 1676 (1961).

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