# The concentration of suphide ion in 0.1 M HCl solution saturated with hydrogen sulphide is 1.0xx10^(-19)M. If 10 mL of this is added to 5 mL o

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The concentration of suphide ion in 0.1 M HCl solution saturated with hydrogen sulphide is 1.0xx10^(-19)M. If 10 mL of this is added to 5 mL of 0.04 M solution of the following: FeSO_(4), MnCl_(2), ZnCl_(z) and CdCl_(2). In which of these solutions precipitation will take place?

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Precipitation will take place in the solution for which ionic product is greater than solubility product. As 10 mL of solutio containing S^(2-) ion is mixed with 5 mL of metal salt solution, after mixing
[For[S^(2-)]:
M_(1)V_(1)=M_(2)V_(2)
10^(-19)xx10=M_(2)xx15, M_(2)=[S^(2-)]=6.67xx10^(-20) M
For
[Fe^(2+)]=[Mn^(2+)]=[Zn^(2+)]=[Cu^(2+)]:
M_(1)V_(1)=M_(2)V_(2)
0.04xx5=M_(2)xx15 rArr M_(2)=1.33xx10^(-2) M
i. Q_(sp)=[Fe^(2+)][S^(2-)]=1.33xx10^(-2)xx6.67xx10^(-20)
=8.77xx10^(27)
[Q_(sp) lt K_(sp), no precipitation]
:. Ionic product each of these will be
=[M^(2+)][S^(2-)]=8.77xx10^(-27)
As this greacter then the K_(sp) of ZnS, and CdS, therefore ZnS and CdS solution will be precipitated and FeS and MnS will not be precipitated.