group 2 the copper group
4
Separation and Analysis of Group II Ions The Group II ions are separated from those in Group III by adding hydrogen sulfide to the mixture in acidic solution. We use an organic precursor, thioacetamide (CH 3 CSNH 2 ), which decomposes to hydrogen sulfide in the presence of acid according to the net reaction CH 3 CSNH 2 + 2 H 2 O CH 3 CO 2 - + NH 4 + + H 2 S The Group II ions precipitate as sulfides on reaction with S 2- from H 2 S
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Most common oxidation state = Bi³⁺ The free ion is strongly hydrolyzed, forming insoluble basic saltsOnly common oxidation state in aqueous systems Halides, nitrates, sulfate, and acetate of Cadmium are soluble in water Most cadmium salts are colorless CdS = Yellow CdO = Yellow brown Forms complex ions with common ligands (Halides, CN⁻, NH₃
Transcript of group 2 the copper group
Separation and Analysis of Group II Ions The Group II ions are separated from those in Group III by adding hydrogen sulfide to the mixture in acidic solution. We use an organic precursor, thioacetamide (CH3CSNH2), which decomposes to hydrogen sulfide in the presence of acid according to the net reaction
CH3CSNH2 + 2 H2O CH3CO2- + NH4+ + H2S
The Group II ions precipitate as sulfides on reaction with S2- from H2S
Group 2 The copper group Bi3+, Cu2+, Sn2+, Sn4+
Bi3+, Cu2+, Sn2+, Sn4+ These ions precipitate as the sulfides from0.3M HCl containing H2S.
Group 2 The copper group Bi3+, Cu2+, Sn2+, Sn4+ These ions precipitate as the sulfides from0.3M HCl containing H2S.
Rationale: Soft acids react with a very soft base.
