Question

QUALITATIVE ANALYSIS OF GROUP II CATIONS 

Qualitative analysis is a method for identifying the elements present in a unknown mixture. For this purpose, metal cations are broadly classified into three groups based upon their solubilities. 

Group I cations, Pb2+, Ag, and Hg22+ form insoluble chlorides. 

Group Il cations, Cu2+, B12+, Hg2+, Cd2+ Sn4+, Sb2+ form insoluble sulfides belowyph 0.5 

Group III cations, Al3+, Cr3+.Co3t felt Mn2+, Ni2+, Zn2+ form insoluble sulfides above pH 9. 

Group IV cations, Ba 2+, Ca2+, Mg2+, Na+, 

K+, NH4+, are the remaining common cations. 

The alkaline earth members of this group form insoluble carbonates while the alkaline elements are identified by flame tests. The ammonium ion is detected by a litmus test. These groups are easily separated by their markedly different solubilities. Separating the cations within a given group is more difficult but based upon the same principle, as will be shown in the experimental section. 

NOTE: THE GROUPS USED FOR QUANTITATIVE ANALYSIS ARE SOLELY BASED ON SOLUBILITY. THEY DO NOT IN ANY WAY CORRESPOND TO THE GROUPS OF THE PERIODIC TABLE 

GROUP II CATIONS: Cu2+, Bi2+, Hg2+, Ca2+, Sn 4+ Sb2+ 

Answer 1