工业混合碱各组分含量测定——一种综合型实验方案设计

Design of a Comprehensive Experiment for Determination of Each Component in Industrial Mixed Alkali

利用两类双指示剂法、BaCl_(2)法和电位滴定法等4种实验方法,分别测定了工业混合碱(NaOH+Na_(2)CO_(3))Ⅰ和混合碱Ⅱ(Na_(2)CO_(3)+NaHCO_(3))溶液中NaOH、Na_(2)CO_(3)与NaHCO_(3)等3种成分的质量浓度(即单位体积溶液中组分质量)。计算和比较了不同分析方法测定结果的误差和标准偏差,对不同分析方法测定结果进行了显著性检验,并分析了产生误差及造成显著性差异的原因。结果表明:电位滴定法的准确度和精密度均较好,BaCl_(2)法的准确度和精密度较差;BaCl_(2)法与其他3种方法测定结果的数据之间存在显著性差异。本文内容不仅对工业混合碱中各组分含量测定方法提供了一个参考,而且为酸碱滴定实验教学提供了一个综合型实验项目的设计方案。

Four experimental methods,including two double-indicator methods,the BaCl_(2)method and the potentiometric titration method were developed for determining the mass concentration(Mass of components in unit volume of solution)of NaOH,Na_(2)CO_(3)and NaHCO_(3)in two types of industrial mixed alkali solutions,i.e.,solutionsⅠ(Na OH+Na_(2)CO_(3))andⅡ(Na_(2)CO_(3)+NaHCO_(3)).Errors and standard deviations of the four analytical methods were calculated and compared based on the measurements.Significance tests were also performed on the results of the four methods,and possible factors/causes that led to poor accuracy and significant differences were also discussed.It was concluded from the experimental results that the potentiometric titration offered the highest accuracy and precision,whereas the BaCl2method suffered from the lowest accuracy and precision from among the four methods.The results also showed significant differences between the BaCl_(2)method and the other three methods.This paper not only provides a reference for the accurate determination of each component in industrial bases,but also supplies a comprehensive experimental protocol for acid-base titration teaching experiments.