Question

Describe a method that can be used to separate each of the following mixtures of metal ions.

A. Ag+, Pb2+

B. Mn2+, Fe3+

C. Ni2+, Al3+

D. Cu2+, Ni2+

Answer 1

A) Use the "standard" qualitative analysis procedure referred to as "Group 1"

This is where chloride ion is used to precipitate both metal ions.

Ag+ + dill HCl --------> AgCl white precipitate

Pb2+ + dill HCl ---------> PbCl2 white precipitate

both precipitate dissolve in NH3

PbCl2 no change and AgCl dissolves [Ag(NH3)2 formed

b) Mn2+ and Fe3+

both dossolves in dill HCl

Fe(OH)3 + 3HCl -----> FeCl3 + 3H2O

MnS + 2HCl ----> MnCl2 + H2S

take salt and few drops of concentration HNO3 or H2S gas and boil the solution and then add NH4Cl and NH4OH

Fe(OH)3 - reddish brown precipitate

MnS - buff coloured pricipitate

c) Ni2+ and Al3+

both dossolves in dill HCl

and take salt and few drops of concentration HNO3 or H2S gas and boil the solution and then add NH4Cl and NH4OH

Al(OH)3 - green precipitate

NiS - black pricipitate

d) Cu2+ and Ni2+

both dossolves in dill HCl

and take salt and few drops of concentration pass H2S gas in presence of HCl

black ppt of (Cus) cu2+ obtaine and other one solution not ppt at that time the

and boil the solution and then add NH4Cl and NH4OH

and after it NiS( Ni2+) ppt obtained which is black colour.