中华医学超声杂志

应用化学 ›› 1992, Vol. 0 ›› Issue (4): 46-51.

• 研究论文 • 上一篇    下一篇

铵离子对玻璃电极不对称电势的影响

赵凯元, 张宏力   

  1. 苏州铁道师范学院化学系, 苏州 215009
  • 收稿日期:1991-02-25 修回日期:1991-11-19 出版日期:1992-08-10 发布日期:1992-08-10

THE INFLUENCE OF NH4+-ION ON UNSYMMETRICAL POTENTIAL OF GLASS-ELECTRODE

Zhao Kaiyuan, Zhang Hongli   

  1. Department of Chemistry, Suzhou Railway Teachers College Suzhou 215009
  • Received:1991-02-25 Revised:1991-11-19 Published:1992-08-10 Online:1992-08-10

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摘要： 本文测定了下列电池在25℃,总离子强度为0.1,0.5,1.0,2.0和13.0mol·kg-1的电动势(emf): (1) Ag|AgCl|HCl(mA)+NH4Cl(mB)+H2O|pH玻璃电极 (2) Pt(黑)|H2(latm)|HCl(mA)+NH4Cl(mB)+H2O|AgCl|Ag因NH4+的干扰,电池(1)不遵从Nernst响应。按离子交换原理导出玻璃电极不对称电势遵从下式:εGo=εG'o+RT/Fln[1+Kα(1+βyB)yB/(1-yB)]式中εG'o为NH4Cl摩尔分数yB=0时的不对称电势;K为离子交换平衡常数,α,β为实验参数。

关键词: 玻璃电极, 不对称电势, 铵离子

Abstract: The electromotive forces of the following cells1. Ag|AgCl|HCl(mA)+NH4Cl(mB)+H2O|Glass-eleetrode2. Pt(black)|H2 (latm)|HCl(mA)+NH4Cl(mB)+H2O|AgCl|Ag have been measured at total molalities of 0.1, 0.5, 1.0, 2.0 and 3.0 mol.kg-1 at 25℃. The potential of the glass-eteetrode was found not to be in agrtement with Nernst equation due to the effect from NH4+.The unsymmetrical potential of the glass-electrode have been derived:εGo=εG'o+RT/FlN[1+Kα(1+βyB)yB/(1-yB)] where yB is malar fraction of NH4Cl,εG'o is unsymmetrical potential of glass-electrode at yB=0. K is an equilibrium constant for ion-exchange, α and β are experimental parameters.

Key words: glass-electrode, unsymmetrical potential, ammonium ion

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