A Selective Method of Qualitative Analysis for the Copper-Tin Group Cations

Salah M. Sultan

Department of Chemistry, College of Science King Saud University, Riyadh-11451 P. O. Box 2455, Saudi Arabia.

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ABSTRACT:

Thiocyanate reagent has been used the first time for qualitative analysis of the Copper-Tin Group cations as sulphides through its decomposition and homogeneous generation of hydrogen sulphide gas in sulphuric acid media. A granular and dense precipitate has occurred slowly within five minutes heating on water bath. The method has been considered selective for the copper-tin group cations since the zinc group cations are soluble in acidic media. 0 8 to 2.0 M sulphuric acid in solution has been found adequate for precipitating all the cations except the cadmium that precipitated in the range of 3.3 to 5 M. Advantages and disadvantages of the use of thiocyanate over gaseous hydrogen sulphide and or thioacctamide reagent have been discussed.

KEYWORDS:

Qualitative; Analysis;Copper-Tin