大学化学 >> 2021, Vol. 36 >> Issue (6): 2008008.doi: 10.3866/PKU.DXHX202008008

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酸碱滴定中强碱滴定弱酸滴定初始曲线的数学解释——以NaOH滴定HAc为例

孙树喆1,2, 张泽浩2,3, 张斌1,*()   

  1. 1 山东大学化学与化工学院, 济南 250100
    2 山东大学泰山学堂, 济南 250100
    3 山东大学生命科学学院, 山东 青岛 266237
  • 收稿日期:2020-08-03 录用日期:2020-08-11 发布日期:2020-09-10
  • 通讯作者: 张斌 E-mail:binzhang68@sdu.edu.cn
  • 作者简介:张斌, Email: binzhang68@sdu.edu.cn
  • 基金资助:
    “基础学科拔尖学生培养计划”研究课题(20180212)

Mathematical Interpretation of Initial Curve of Acid-Base Titration between Strong Base and Weak Acid: Taking NaOH and HAc as an Example

Shuzhe Sun1,2, Zehao Zhang2,3, Bin Zhang1,*()   

  1. 1 School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
    2 Taishan College, Shandong University, Jinan 250100, China
    3 School of Life Sciences, Shandong University, Qingdao 266237, Shandong Province, China
  • Received:2020-08-03 Accepted:2020-08-11 Published:2020-09-10
  • Contact: Bin Zhang E-mail:binzhang68@sdu.edu.cn

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摘要：

NaOH滴定HAc的酸碱滴定曲线（武汉大学主编的《分析化学》第6版上册）在滴定初始阶段存在明显的凸出部分，与同浓度条件下NaOH滴定HCl的滴定曲线有显著差异。本文利用酸碱反应中的各种平衡关系式推导出该曲线的数学表达式，结合图像证明曲线符合酸碱滴定中的相关规律，解释了强碱滴定不同弱酸初始滴定曲线差异的原因和影响因素。

关键词: 分析化学, 酸碱滴定, 滴定曲线, 酸碱平衡, 数学模型

Abstract:

In the acid-base titration curve of titration from NaOH to HAc, shown in the sixth edition of Analytical Chemistry edited by Wuhan University, we found that there was an obvious protruding part of the curve at the initial stage of titration, which was significantly different from the curve of titration from NaOH to HCl at the same concentration. In this paper, the mathematical expression of fitting the curve is derived by using various equilibrium relations in acid-base reaction. The correlation law of acid-base titration is proved by combining with the image of mathematical function. The mathematical model can explain not only the differences between two curves, but also the reasons and influencing factors of the initial titration curve difference of weak acids by strong alkali titration.

Key words: Analytical chemistry, Acid-base titration, Titration curves, Acid-base equilibrium, Mathematical model