银量回滴测定氯离子方法(Volhard法)的改进

• 作 者: 何久康
• 机 构: 内蒙古大学化学系,
• 出 处: 内蒙古大学学报(自然科学版)
• 发表日期: 1981年01期
• 关键词: 沉淀过滤 氯离子 Volhard 硫氰酸银 等当点 硫氰酸铁 硫氰酸根 回滴法 有机溶剂 过滤法

前言银量回滴法测定氯离子的优点是可以在酸性液液中进行测定。但本方法存在着由于氯化银与硫氰酸银溶解度的差别,等当点后微过量的硫氰酸根会与溶液中的氯化银沉淀进行反应,从而使指示终点的硫氰酸铁橙红色消失。这样会给分析结果引入很大误差。前人曾采取许多措施,如:将氯化银沉淀过滤掉;加入与水不相混溶的有机溶剂等办法以减低分析结果的误差。

Preface The silver back drop method for the determination of chloride ion has the advantage that it can be measured in an acidic liquid. However, due to the difference between the solubility of silver chloride and silver thiocyanate in this method, a slight excess of thiocyanate after the equivalence point reacts with the silver chloride precipitate in the solution, so that the end point of ferric thiocyanate Red disappears. This will introduce a great error in the analysis results. Many people have taken many measures, such as: the silver chloride precipitate filtered out; adding water-immiscible organic solvents and other methods to reduce the error analysis results.