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本文重新研究了EDTA絡合量法中用Cu-PAN系統滴定Ca~(++),Ba~(++),Mg~(++),Al~(+++),Cr~(+++),Zn~(++),Fe~(+++),Pb~(+++),Bi~(+++),Hg~(++),Cu~(++)等的pH、溫度、指示剂用量等条件,测定准确度为1％.建立了用Cu-PAN系統滴定鉻盐及鋇盐的方法,測定終点較用鉻黑T指示剂明显.測定了Cu-PAN絡合物的組成为1:1,稳定常数为:pH2,1.4×10~6;pH4,1.9×10~6;pH 6,1×10~5;pH 8,7.5×10~4;pH 10,2.1×10~5.根据这些結論,改进了Cu-PAN系統的滴定方法。
In this paper, the titration of Ca~(++), Ba~(++), Mg~(++), Al~(+++), Cr~(++) with the Cu-PAN system in the EDTA complex method was re-examined. +), Zn~(++), Fe~(+++), Pb~(+++), Bi~(+++), Hg~(++), Cu~(++), etc. , temperature, indicator dosage and other conditions, the measurement accuracy is 1%. A method for titrating chromium salts and cesium salts using the Cu-PAN system was established. The end point was measured more clearly than the chrome black T indicator. The Cu-PAN complex was determined. The composition of the substance is 1:1, the stability constant is: pH2, 1.4×10~6; pH4, 1.9×10~6; pH 6, 1×10~5; pH 8, 7.5×10~4; pH 10, 2.1 ×10~5. Based on these conclusions, the titration method of the Cu-PAN system was improved.