碳酸钠与盐酸分步反应pH曲线误差探究  

Exploration of pH Curve Errors in the Stepwise Reaction of Sodium Carbonate with Hydrochloric Acid

作　　者：孟庆华 刘茂臻 邢蓓蓓 刘翠 MENG Qing-Hua;LIU Mao-Zhen;XING Bei-Bei;LIU Cui(College of Chemistry and Materials Science,Jiangsu Normal University,Xuzhou 221116,China)

机构地区：[1]江苏师范大学化学与材料科学学院,江苏徐州221116

出　　处：《化学教育(中英文)》2025年第3期86-92,共7页Chinese Journal of Chemical Education

基　　金：2023年江苏省高校哲学社会科学项目(2023SJYB1077)。

摘　　要：采用自行搭建的实验装置探究了用数字化技术获得的碳酸钠与盐酸分步反应的pH曲线第1步消耗的盐酸量V_(1)与第2步消耗的盐酸量V_(2)存在差异的原因。实验结果表明V_(1),V_(2)产生差异主要是由搅拌速度、滴定速度、溶液浓度、溶液温度等条件影响pH传感器对pH响应的滞后效应造成的。在滴定过程中溶液充分搅拌的情况下,滴定速度越快,V_(1)大于V_(2)且差值越大;Na_(2)CO_(3)浓度越高时其溶液黏度越大,使pH传感器对pH响应的滞后效应加剧;溶液温度较高时,溶液黏度降低,使V_(1)与V_(2)差值变小;当Na_(2)CO_(3)浓度较低时,水中溶解的CO_(2)与碳酸钠溶液反应生成的碳酸氢钠量对V_(1)与V_(2)差值的影响不能忽略,配制溶液的纯净水最好煮沸冷却后即用。This paper investigated the reason for the difference between the amount of hydrochloric acid V_(1)consumed in the first step and the amount V_(2)consumed in the second step of the stepwise reaction between sodium carbonate and hydrochloric acid,which obtained using a self-constructed experimental setup and digital technology,by examining the pH curve.The experimental results indicated that the main reason for the difference between V_(1)and V_(2)was the effect of stirring speed,titration rate,solution concentration,and solution temperature on the pH sensor's lag response.Under conditions of sufficient stirring during the titration process,with faster titration rate,V_(1)was greater than V_(2)and the difference was larger.A higher concentration of sodium carbonate led to higher solution viscosity,exacerbating the lag response of the pH sensor.On the other hand,higher solution temperature decreased the solution viscosity,resulting in a smaller difference between V_(1)and V_(2).When the sodium carbonate concentration was low,the amount of sodium bicarbonate formed by the reaction between dissolved carbon dioxide in the water and sodium carbonate solution could not be neglected,and the purified water of the preparation solution was best used after boiling and cooling.

关 键 词：滞后效应 PH传感器 分步反应 碳酸钠 盐酸 

分 类 号：G633.8[文化科学—教育学]