A solution containing a mixture of metal cations was treated with dilute HCl and

Question

A solution containing a mixture of metal cations was treated with dilute HCl and no precipitate formed. Next, H2S was bubbled through the acidic solution. A precipitate formed and was filtered off. Then, the pH was raised to about 8 and H2S was again bubbled through the solution. A precipitate again formed and was filtered off. Finally, the solution was treated with a sodium carbonate solution, which resulted in no precipitation. Which metal ions were definitely present, which were definitely absent, and which may or may not have been present in the original mixture?

Explanation / Answer

Answer – We are given the mixture of metal cations was treated with dilute HCl and no precipitate formed, means there are definitely absent metal ions are Ag+, Pb2+ and Hg22+, since we know the chlorides are only precipitated with these ions and with other metal ions are soluble. So these three metal ions are definitely absent.

Then this mixture was treated with H2S through the acidic solution and formed precipitated, so there are metal ions which gives precipitate with H2S are Bi3+, Cu2+, Pb2+, Cd2+, Hg2+, Sb3+, Sn2+ and Sn4+. Now when the pH was raised to about 8 and H2S was again bubbled through the solution and we know in the basic condition there is precipitated from with metal ion are Fe2+,Co2+, Ni2+, Mn2+, Al3+, Cr3+, Fe3+,and Zn2+. So metal ions which may or may not have been present in the original mixture are are Bi3+, Cu2+, Pb2+, Cd2+, Hg2+, Sb3+, Sn2+ Sn4+, Fe2+,Co2+, Ni2+, Mn2+, Al3+, Cr3+, Fe3+,and Zn2+.

The remaining solution was treated with sodium carbonate solutionand there is no precipitation, means in ther original solution there are Ba2+, Ca2+, Mg2+,and Sr2+ not present.

So in the solution there are definitely present metal ions are Li+, Na+, K+ and NH4+.

In the original solution definitely absent metal ions are Ag+, Pb2+, Hg22+, Ba2+, Ca2+, Mg2+,and Sr2+

metal ions which may or may not have been present in the original mixture are are Bi3+, Cu2+, Pb2+, Cd2+, Hg2+, Sb3+, Sn2+ Sn4+, Fe2+,Co2+, Ni2+, Mn2+, Al3+, Cr3+, Fe3+,and Zn2+.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.