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文献用改进的方法合成了邻、邻＇-二氨基偶氮苯(DAAD),并研究了与铜的显色反应。本文探讨了DAAD用作铜的络合滴定指示剂的可能性。研究表明,在pH4.5醋酸-醋酸钠的缓冲溶液中,加入5滴0.04％DAAD指示剂。以0.01M EDTA标准溶液进行滴定,溶液颜色由紫红色变为黄绿色(铜量多时为绿色)。终点变化敏锐、准确度高、选择性好,实验表明,该法可用于矿石中铜的测定。实验部分 (一)试剂与仪器铜标准溶液,称取金属铜(99.9％)1.0g,置于250ml烧杯中,加入1:1硝酸15Ml,加热
In the literature, ortho - o - diaminoazobenzene (DAAD) was synthesized by a modified method and the color reaction with copper was studied. This article explores the possibility of using DAAD as a complexometric titration indicator for copper. Studies have shown that in a pH 4.5 acetate-sodium acetate buffer solution, 5 drops of 0.04% DAAD indicator are added. Titration with 0.01M EDTA standard solution, the solution color from purple to yellow-green (when the amount of copper is green). Sharp changes in the end point, high accuracy, good selectivity, experiments show that the method can be used for the determination of copper in ores. Experimental part (A) reagents and equipment Copper standard solution, weighed copper (99.9%) 1.0g, placed in 250ml beaker, add 1: 1 nitric acid 15Ml, heated