Osmotic coefficients and activity coefficients of lodic acid at high concentrations
Osmotic coefficients and activity coefficients of lodic acid at high concentrations
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高浓度碘酸的渗透系数和活度系数
DOI：
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发表时间：
1974
期刊：
影响因子：
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通讯作者：
R. Robinson
中科院分区：
文献类型：
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作者：
S. Goldman;R. Bates;R. Robinson
等压蒸气压测量已用于确定 25°C 时摩尔浓度为 0.1 至 17 摩尔-kg−1 的碘酸水溶液的渗透系数。等压标准是氯化钠溶液和硫酸溶液。由于碘酸具有腐蚀性，因此使用铂杯。碘酸的化学计量活性系数通过 Gibbs-Duhem 积分得出。摩尔浓度大于 0.5 摩尔-kg−1 的溶液的活度系数不能用两个平衡来解释，即碘酸的酸性解离和离子 H(IO3)2− 的形成，Pethybridge 和 Prue 证明了这一点，以充分解释稀溶液中的行为。在浓溶液中，活度系数出乎意料地小，表明形成了碘酸的中性聚集体。二聚体和四聚体，或者三聚体和四聚体的存在，可以解释摩尔浓度高达 7 摩尔-kg−1 时观察到的结果。
Isopiestic vapor pressure measurements have been used to determine the osmotic coefficients of aqueous solutions of iodic acid at molalities from 0.1 to 17 mole-kg−1 at 25°C. The isopiestic standards were solutions of sodium chloride and solutions of sulfuric acid. Because of the corrosive nature of iodic acid, platinum cups were used. Stoichiometric activity cofficients of iodic acid were derived by a Gibbs-Duhem integration. The activity coefficients for solutions of molality greater than 0.5 mole-kg−1 cannot be accounted for in terms of the two equilibria, namely, the acidic dissociation of iodic acid and formation of the ion H(IO3)2−, shown by Pethybridge and Prue to explain adequately the behavior in dilute solutions. The activity coefficient is unexpectedly small in concentrated solutions, suggesting the formation of neutral aggregates of iodic acid. The presence of dimers and tetramers, or alternatively trimers and tetramers, can explain the observed results up to a molality of 7 mole-kg−1.