Expert: Dr. Jeffery Raymond - 12/24/2011

Question
Hello Dr. Raymond.

Could you please clarify this point for me? It's not a homework question. I'm preparing for a college entry test and came across it.

Y(MnO4)3 shows a very small solubility in water. How would you determine its solubility product experimentally?
The problem is I'm not sure which reagents to use for a titration for this.

Answer
Sorry for the delay: It is holiday season and I was away with friends and family.

I am no expert at heavy metal determination, but I know that Yttrium has been detected at low levels for a long time using bright dyes which respond to complexation.  Here is a link to one of the original methods.  It is a paper that you can't get without web access through a university of something similar, but you can see the first page, which has all the basics you need to know.

http://pubs.acs.org/doi/abs/10.1021/ac60164a009

Also, in a general sense, a pH indicator for someplace near pH 7 (phenol red or neutral red are popular) is always a good choice for trace heavy metal detection.  You then use a multidentate ligand like EDTA to bind to the Yttrium in solution. Once the Yttrium is consumed you should be left with a MnO4 salt in solution and the color changed indicator as well as the EDTA bound metal.

I hope this helps and free to ask me a follow up if you need more help.

Have a happy new year!