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Solubility and Solubility Product of Gypsum in Soil Solutions and Other Aqueous Solutions
Author(s) -
Bennett A. C.,
Adams Fred
Publication year - 1972
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1972.03615995003600020025x
Subject(s) - solubility , solubility equilibrium , gypsum , aqueous solution , chemistry , ionic strength , inorganic chemistry , electrolyte , activity coefficient , materials science , metallurgy , organic chemistry , electrode
The solubility of CaSO 4 ·2H 2 O in several soils and dilute aqueous electrolytic media was measured. The ionic strength of electrolytic media ranged from 0.059 to 0.314; the solubility product of gypsum in these solutions ranged from 2.13 × 10 ‐5 to 2.79 × .10 ‐5 with an average value of 2.51 × 10 ‐5 . In displaced soil solutions, the solubility product of gypsum ranged from 2.41 × 10 ‐5 to 2.92 × 10 ‐5 ; the average was 2.73 × 10 ‐5 . The solubility product of gypsum in water was 2.58 × 10 ‐5 . The mean ionic activity coefficient of gypsum in solutions of different ionic strengths was computed using analytical data from aqueous electrolytic media and the known solubility product, i.e., 2.58 × 10 ‐5 . The plot of this mean ionic activity coefficient versus the square root of gross solution ionic strength, i.e., no correction for ion pairing, for mixed‐SO 4 2‐ systems allowed accurate determination of the solubility product of gypsum in the soil solutions using only analytical data.