大学化学 >> 2016, Vol. 31 >> Issue (10): 68-73.doi: 10.3866/PKU.DXHX201601035

化学实验 上一篇    下一篇

活度系数法测定A2B型难溶盐的溶度积——以Ag2SO4为例

李瑜*(),朱金华,饶秋华,宋玉苏,周子龙,郑炀   

  • 发布日期:2016-11-02
  • 通讯作者: 李瑜 E-mail:55491983@qq.com
  • 基金资助:
    海军工程大学教学研究项目(2015JB-06,NUE2013224)

Solubility Product Determination ofA2BType Insoluble Salts by theActivity Coefficient Method: TakingAg2SO4 as an Example

Yu LI*(),Jin-Hua ZHU,Qiu-Hua RAO,Yu-Su SONG,Zi-Long ZHOU,Yang ZHENG   

  • Published:2016-11-02
  • Contact: Yu LI E-mail:55491983@qq.com
  • Supported by:
    海军工程大学教学研究项目(2015JB-06,NUE2013224)

摘要:

实验假设水溶液中Ag+和SO42-的浓度非常低时,其活度无论处于同一体系还是在不同体系均相同。依此设计原电池,使该原电池的电池反应为Ag2SO4(s)→2Ag+(aq)+SO42-(aq),采用补偿法测量一定温度下此原电池中AgNO3溶液浓度和K2SO4溶液浓度发生变化时的电池电动势E;。依据能斯特方程和Debye-Huckel极限公式,推导出原电池标准电动势E与电解质的平均活度系数γ±及溶液浓度的关系,用外推法作图得到此电池反应的标准电动势E。由平衡常数与原电池标准电动势的关系,得到Ag2SO4的溶度积Ksp(Ag2SO4)。

关键词: 活度系数法, 原电池, 溶度积常数

Abstract:

Taking the assumption that activity of silver ion and sulfate ion of very low concentration is constant in any aqueous solution,the primary cell was designed for the cell reaction of Ag2SO4(s)→2Ag+(aq)+SO42-(aq).The compensation method was used to obtain the electromotive force of the primary cell when the concentrations of AgNO3 and K2SO4 changed.The relationship between electromotive force and the mean activity coefficients of electrolytes as well as the solution concentration was deduced according to the Nernst equation and the limit Debye-Huckel formula.Standard electromotive force E was obtained by extrapolation.Finally,the solubility product of silver sulfate was calculated through the relationship between equilibrium constant and electromotive force of the primary cell.

Key words: The activity coefficient method, Primary cell, Solubility product

MSC2000: 

  • G64