Published isopiestic molalities for aqueous NaTcO4 and HTcO4 solutions at 25°C have been reexamined. Our calculations indicate that published smoothed values of the osmotic coefficients ϕ and mean molal activity coefficients γ± of NaTcO4 are substantially in error, by up to 100% for ϕ and 300% for γ±. Published smoothed values of ϕ and γ± for HTcO4 solutions are in somewhat better agreement with the input data, but the reported ϕ are sometimes higher and sometimes lower than experimental values, by up to 6%. Consequently, we have reanalyzed isopiestic data for these two systems, and find that errors arose in representing the data mathematically. We report parameters for an extended form of the specific ion interaction equations and for Pitzer's equations, and corrected values of ϕ and γ± are tabulated for aqueous NaTcO4 and HTcO4.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
G. E. Boyd,J. Chem. Educ. 36, 3 (1959).
R. H. Busey, R. B. Bevan, Jr., and R. A. Gilbert,J. Chem. Thermodyn. 4, 77 (1972).
J. A. Rard, M. H. Rand, and J. R. Thornback,Chemical Thermodynamics of Technetium, H. Wanner and I. Forest, eds., (Nuclear Energy Agency, Organisation for Economic Co-Operation and Development, Gif-sur-Yvette, France, 1992), to be published.
G. E. Boyd,J. Solution Chem. 7, 229 (1978).
G. E. Boyd,Inorg. Chem. 17, 1808 (1978).
W. T. Smith, Jr., J. W. Cobble, and G. E. Boyd,J. Am. Chem. Soc. 75, 5773 (1953).
W. J. Hamer and Y.-C. Wu,J. Phys. Chem. Ref. Data 1, 1047 (1972).
M. H. Lietzke and R. W. Stoughton,J. Phys. Chem. 66, 508 (1962).
R. A. Robinson and R. H. Stokes,Electrolyte Solutions, 2nd edn., (Butterworths, London, 1965).
J. A. Rard and D. G. Miller,J. Chem. Eng. Data 27, 169 (1982).
J. A. Rard, A. Habenschuss, and F. H. Spedding,J. Chem. Eng. Data 22, 180 (1977).
K. S. Pitzer, in,Activity Coefficients in Electrolyte Solutions, Vol. I, R. M. Pytkowicz, ed., (CRC Press, Boca Raton, Florida, 1979), Chap. 7. We usedA ϕ=0.3915 as recommended in the revised version of this article (in press for the second edition).
I. Grenthe and H. Wanner,Guidelines for the Extrapolation to Zero Ionic Strength, TDB-2.1 (Nuclear Energy Agency, Organisation for Economic Co-Operation and Development, Gif-sur-Yvette, France, 1989).
About this article
Cite this article
Rard, J.A., Miller, D.G. Corrected values of osmotic and activity coefficients of aqueous NaTcO4 and HTcO4 at 25°C. J Solution Chem 20, 1139–1147 (1991). https://doi.org/10.1007/BF01075131
- Osmotic coefficients
- activity coefficients
- aqueous solutions
- sodium pertechnetate
- pertechnetic acid