物理化学学报 >> 2003, Vol. 19 >> Issue (02): 115-119.doi: 10.3866/PKU.WHXB20030205

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乙二醇和水混合溶剂多组分电解质热力学

王琴萍;吕殿祯;张莉;孙雪丽;杨家振   

  1. 辽宁大学化学系,沈阳　110036
  • 收稿日期:2002-04-01 修回日期:2002-06-28 发布日期:2003-02-15
  • 通讯作者: 吕殿祯 E-mail:ludianzhen@yahoo.com.cn

Thermodynamics of Mixed Electrolytes in Mixed Solvents of Glycol and Water

Wang Qin-Ping;Lü Dian-Zhen;Zhang Li;Sun Xue-Li;Yang Jia-Zhen   

  1. Department of Chemistry, Liaoning University, Shenyang　110036
  • Received:2002-04-01 Revised:2002-06-28 Published:2003-02-15
  • Contact: Lü Dian-Zhen E-mail:ludianzhen@yahoo.com.cn

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摘要： 在乙二醇和水混合溶剂中恒定乙二醇质量分数w=0.1的条件下，应用经典的电动势方法测定无液体接界电池的电动势: Pt，H2 (105 Pa )│HCl (质量摩尔浓度m)， C2H6O2 (w), H2O (1－w)│AgCl-Ag (A) Pt，H2 (105 Pa )│HCl (mA), NaCl(mB), C2H6O2 (w), H2O (1－w)│AgCl-Ag (B) 根据测得电池(A)的电动势，确定混合溶剂中AgCl-Ag电极的标准电极电势，讨论了HCl的迁移性质.利用电池（B）的电动势，计算出HCl的活度系数γA.结果表明，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. 进一步讨论了混合物中HCl的相对偏摩尔焓和介质效应.

关键词: 活度系数, Harned规则, 电动势, 介质效应, 乙二醇

Abstract: The thermodynamic properties of system HCl-NaCl-C2H6O2-H2O was studied by EMF measurement in the cells without liquid junction: Pt, H2 (105 Pa)|HCl (m), C2H6O2 (w), H2O (1－w) | AgCl-Ag (A) Pt, H2 (105 Pa)|HCl (mA), NaCl (mB), C2H6O2 (w), H2O（1－w）| AgCl-Ag (B) at constant total ionic strength I=0.5, 1.0, 1.5 and 2.0 mol•kg－1, from 5 to 45 ℃, where mA and mB are the molalities of HCl and NaCl, respectively, w is the mass fraction of glycol in the mixed solvent, which is 10％ during all measurement. The standard electrode potential of Ag-AgCl in the mixed solvent has 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 solutions still obey Harned’s Rule. The standard transfer Gibbs free energies of HCl have been calculated. The primary, secondary and total medium effects of HCl have been calculated and discussed.

Key words: Activity coefficients, Harned’s rule, EMF, Medium effect, Glycol