双电解质溶液HCl-H_2O-MCl_n(M=Ni,Cu,Na,Fe)中水活度系数的计算

ACTIVITY COEFFICIENTS OF WATER IN AQUEOUS SOLUTION OF DOUBLE ELECTROLYTES, HCl AND MCln (M=Ni, Cu, Na AND Fe)

将水溶液中电解质处理成它们的分子形式而不是它们的离子形式，并基于两电解质之间的相互作用能相对于它们与水的相互作用能可以忽略这一假设前提，提出了简化的正规溶液模型，以计算双电解质溶液体系ＨＣｌＨ２ＯＭＣｌｎ（Ｍ＝Ｎｉ，Ｃｕ，Ｎａ，Ｆｅ）中水的活度系数。模型中所包含的两个参数为组元对的相互作用能，由实验数据估算了所讨论体系中涉及的５个组元对的相互作用能。不同双电解质体系得到的ＨＣｌＨ２Ｏ组元对的相互作用能极为吻合，表明所提出的模型是合理的。

In order to calculate the activity coefficients of water in the aqueous solution systems of double electrolytes, HCl and MCln (M=Ni, Cu, Na and Fe), a simplified regular solution model has been derived based on the assumption that the electrolytes in the aqueous solution can be treated as independent particles in stead of their ion forms, and that the interaction of the component pair HClMCln in the aqueous solution is very weak as compared with the component pairs HClH2O and H2OMCln. The interchange energies of the component pairs in the discussed systems, HClH2O, H2ONiCl2, H2OCuCl2, H2ONaCl and H2OFeCl3, have been evaluated from the experimental data to be -69 400 Jmol-1, -212 600 Jmol-1, -90 550 Jmol-1, -42 450 Jmol-1 and -198 310 Jmol-1. The interchange energy HClH2O between HCl and H2O component pair obtained from four different double electrolyte solution systems is almost the same within experimental errors, which indicates that the present model is reasonable to certain extent.