Question

I'm in serious need of help. I worked on the Qualitative Analysis of Cations Lab, Groups I and II.

For group I, the possible Ions in a solution were Ag+1, Pb+2, Hg2+2. I was able to sucessfully percipitate out and confirm the presense of Silver.

For Group II, the possible Ions were Hg2+, PB2+, Bi2+, Cu2+.

The problem is I should have percipitated out three Cations and only found one. I know with certainty that I did not have Mercury at any time, as I never had a black percipitate in my solution, or left behind on the filtrate paper. I have a feeling that I acutally had Pb2+ in the group I, but the test tube I was using was old, and dirty so I may have mistaken cloudiness on my solution for an old test tube.

Based on this information, is there a way to determine what the possible Ions should habe been, knowing that I had AgCl?

Thanks!

Answer 1

We know that Ag+ Pb+2 and Hg2+2 all the ions give ppt with HCl

Ag+ : it gives white ppt with HCl

Now due to dirty test tube you are getting confused with Pb and Ag

so just do one thing, add hot water to the precipitate, if it dissolves in it then it is PbCl2 ppt and not AgCl

If it is insoluble then it is not PbCl2 ppt.