非水滴定法测定水杨酸钠质量分数实验的改进

Improvement on Determination of Sodium Salicylate by Nonaqueous Acid-Base Titration

非水滴定法测定水杨酸钠质量分数是分析化学实验中重要的教学内容,现有教材中该实验的内容主要是高氯酸标准溶液的标定和水杨酸钠质量分数的测定.针对实验过程中指示剂用量和滴定终点颜色不同对测定结果准确度产生影响等问题,将电位滴定法引入到实验中以更好地确定指示剂的合适用量和判断终点颜色.结合统计分析研究不同滴定终点颜色对水杨酸钠测定准确度的影响,并以此改进后的实验方案作为综合性实验内容用于实验教学中.不仅能加深学生对非水滴定等分析方法原理及其有关理论的理解,而且能够培养学生严谨的科学态度和良好的实验素养.

The determination of sodium salicylate content using non-aqueous titration is important in the experiment teaching of analytical chemistry, and the current determination method is based on the use of perchloric acid standard solution. Potentiometric titration analysis method was used to study the effects of indicator dosage and the end point color on the accuracy of experimental results. Combined with quantitative analysis, this newly designed comprehensive experiment deepened the students’ understanding on the principles and theories of non-aqueous titration, and promoted the cultivation of the students’ rigorous scientific attitudes and experimental abilities.