物理化学学报 >> 1998, Vol. 14 >> Issue (02): 121-126.doi: 10.3866/PKU.WHXB19980205

研究论文 上一篇    下一篇

HCl-NaCl-C3H8O3-H2O体系溶液热力学性质

吕殿祯, 杨家振, 王琴萍, 邓敏, 段继芳, 陈峥   

  1. 辽宁大学化学科学与工程学院,沈阳 110036
  • 收稿日期:1997-04-14 修回日期:1997-07-06 发布日期:1998-02-15
  • 通讯作者: 吕殿祯

Thermodynamic Properties of the System of HCl-NaCl-C3H8O3-H2O

Lv Dian-Zhen, Yang Jia-Zhen, Wang Qin-Ping, Deng Min, Duan Ji-Fang, Chen Zheng   

  1. Department of Chemistry,Liaoning University,Shenyang 110036
  • Received:1997-04-14 Revised:1997-07-06 Published:1998-02-15
  • Contact: Lv Dian-Zhen

摘要:

在恒定丙三醇质量分数x=0.1的条件下,测定了无液接电池(A)和电池(B)的电动势
Pt, H2(1.013×105Pa)|HCl(m), C3H8O3(x), H2O(1-x)|AgCl-Ag             (A)
Pt, H2(1.013×105Pa)|HCl(mA), NaCl(mB), C3H8O3(x), H2O(1-x)|AgCl-Ag  (B)
根据电池(A)电动势确定了丙三醇和水混合溶剂中的Ag-AgCl电极的标准电极电势,讨论了HCl的迁移性质;由电池(B)测得的电动势计算了HCl在该体系中的活度系数γA,计算的结果表明,对于所讨论的体系,在溶液中总离子强度保持恒定,HCl的活度系数服从Harned规则.在溶液组成恒定时,lgγA是温度倒数1/T的线性函数,讨论了混合物中HCl的相对偏摩尔焓及介质效应.

关键词: 标准电极电势;活度系数, 偏摩尔焓

Abstract:

The thermodynamic properties of the system HCl-NaCl-C3H8O3-H2O was studied by means of emf measurement in the following cells without liquid junctions:
Pt, H2(1.013×105Pa)|HCl(m), C3H8O3(x), H2O(1-x)|AgCl-Ag             (A)
Pt, H2(1.013×105Pa)|HCl(mA), NaCl(mB), C3H8O3(x), H2O(1-x)|AgCl-Ag  (B)
at constant total ionic strength I=0.5, 1.0. 1.5 and 2.0mol.kg-1 , from 5 to 45 ℃, where mA and mB are the molalities of HCl and NaCl. respectively, x is the weight fraction of glycerol in the mixed solvent, which was 0.1 during all measurements.
The standard electrode Potential of Ag-AgCl in the mixed solvent have been determined from cell (A). The activity coefficients of HCl, γA in the mixed solvent system have been determined from cell (B). The results show that the activity coefficients of HCl in HCl-NaCl solution still obeys Harned rule, and lgγA is a linear function of the reciprocal of the absolute temperature at constant composition of the mixture. Relative molar enthalpies of HCl LA arc linear function of the ionic strength fraction of NaCl at constant total ionic strength temperature. The standard Gibbs free energies of transfer of HCl have been calculated. The primary secondary and total medium effect of HCl have been calculated and discussed.

Key words: Standard electrode potential, Activity coeffiecient, Relative molar enthalpies