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he Ion-Product Constant of Water to 350°

Journal of Physical Chemistry

By:
and
DOI: 10.1021/j100645a016

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Abstract

The ion-activity product of water, KW0, has been determined to 350?? along the liquid-vapor curve from conductance measurements made between 100 and 350?? on aqueous solutions in the system acetic acid-ammonium acetate-ammonia. Derivation of KW0 requires data on the limiting equivalent conductivities of acetic acid, ammonia, and ammonium acetate, the ionization constants of acetic acid and ammonia, and of the conductivities of pairs of these solutes at a series of concentrations. The limiting equivalent conductivities were indirectly obtained from literature data on the limiting equivalent conductivities of HCl, NaCl, NaOH, NH4Cl, and NaOAc. The ionization constants of acetic acid were obtained from our conductance measurements combined with literature data; constants for ammonia were obtained from the literature. From our conductivities, values of KW0 were obtained between 100 and 350??; these were combined with well established literature values and the combined set analytically smoothed to provide a consistent set of molal constants from 25 to 350??; respective pK's at 150, 250, and 350?? are: for H2O, 11.64, 11.05, and 11.42; for HOAc, 5.22, 5.95, and 7.68; and for NH4OH, 5.11, 5.91, and 7.30.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
he Ion-Product Constant of Water to 350°
Series title:
Journal of Physical Chemistry
DOI:
10.1021/j100645a016
Volume
76
Issue:
1
Year Published:
1972
Language:
English
Publisher:
American Chemical Society
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Physical Chemistry
First page:
90
Last page:
99
Number of Pages:
10