Abstract
The apparent equilibrium constant, K ′1 , for the first acidity constant of carbonic acid has been determined in a lake water of 1.6 mM ionic strength in the temperature interval 4–18°C. The experimental method used comprises pH measurements in situ (NBS scale) with a probe and an IR-method for the selective determination of [H2CO3] and [HCO −3 ] in water samples. In the temperature interval studied the results can be described by the equation logK ′1 =126.39−6320.81/T−19.5682 ln T and are in agreement with the values of K ′1 obtained by the empirical equation presented by Millero [15]. This experimental agreement justifies thermodynamic calculations in the carbonate system based on field data. Also the experimental method described can be used to evaluate the acid-base balance of organic rich natural waters.
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Lidén, J. Equilibrium approaches to natural water systems—Part 2. Schweiz. Z. Hydrologie 44, 393–404 (1982). https://doi.org/10.1007/BF02502299
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DOI: https://doi.org/10.1007/BF02502299