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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: mazzei101 on October 21, 2007, 11:02:59 PM

Title: Qualitative Analysis- Separating ions from solution
Post by: mazzei101 on October 21, 2007, 11:02:59 PM

I have a solution containing one or all of the following ions, Fe3+, K+, and Pb2+. I need to run tests in order to identify the ions that are in the solution. I know I start by adding compounds in order to form precipitates. However, I do not know how to get started. What compounds should I add in order to form precipitates and in what order?
As of now I know adding HCl will react to form PbCl2, a solid. But, I do not know what to do in order to separate the K and Fe. I also know I could add NH3 to form Fe(OH)3. I do know how to handle the solution otherwise. How do I know what to do after I create the first precipitate?
If someone could help me get started by describing some of the compounds I could add and what the resulting compounds are I would greatly appreciate it.

How do I get started?
What do I add, what forms?

Title: Re: Qualitative Analysis- Separating ions from solution
Post by: LQ43 on October 22, 2007, 09:45:42 PM

Start by looking at a solubility chart to see what kind of compounds would be insoluble or soluble. Hint: one of those ions will not give a ppt

Title: Re: Qualitative Analysis- Separating ions from solution
Post by: ARGOS++ on October 23, 2007, 08:40:15 AM

Dear Mazzai101,

Could it be possible you never heard of “Qualitative Cation Analysis”?

Maybe a visual Hint can be helpful, even if in German.
A few Translations therein:
  -  Analysenlösung  =  “Test-Solution”;   und  =  and;   bis  =  till;
  -  Gruppe   =   Group;    Gruppen   =  Groups;
  -  Prüfung und Entfernen der  =  Test  for and Elimination of;
  -  weiβ  =   white;  gelb  =  yellow;  schwarz   =   black;

I hope, that this is giving you at least a "start picture".

Good Luck!

                    ARGOS⁺⁺