5 replies to this topic

[cooperman435]

I currently have a large collection of what I believe are Oxalate's, sodium, strontium and barium I am lead to believe.

Can any of you out there assist or suggest tests that I can do to establish what they are for definite?

Im no chemist nor do I have a collection of regents etc so ideally the tests would need to be easy enough to do and if possible not require any fancy chemicals etc.

I appreciate this is not always (or usually!) possible but as I'm not even 100% sure they are oxalate's any tests that I can do would be a good start to labelling them correctly.

Phill

[cooperman435]

Also if anyone is able to test them for me because I wouldn't be able to carry out the tests myself I can arrange samples :-)

[Adrenaline]

Thats the standard test for oxalates:

Dissolve a bit of your test-substance in a few ml of water. Now add some calcium chloride soultion and a white precipitate will form. Then you have to filter of and dissolve the precipitate in dilute sulfuric acid. Add a dropp! KMnO₄-solution. Start to warm up the solution. If the permangante colour disappears when the solution is getting hotter your substance contained Oxalate.



Testing for kations should be possible with flame colouration.

[Mumbles]

That test works on the assumption that calcium oxalate is significantly less soluble than the parent oxalate. This will work for sodium, but strontium and barium oxalates are both more insoluble than calcium. I would do flame tests, make sure the barium and strontium ones are insoluble in water, and maybe add some vinegar. If it's carbonate it will fizz, if it's hydroxide it will dissolve. It would be difficult to tell apart from sulfate, but there is a test to tell them apart if you have potassium or ammonium dichromate.

Edited by Mumbles, 12 January 2011 - 07:11 PM.

[Maxim]

Im going to rely on my knowledge of some A-level here and presume that if they are all oxalates i.e. Sodium Oxalate, Strontium Oxalate and Barium Oxalate, then im pretty sure you can do displacement reactions with them (someone else will have to contribute the knowledge about the reagents involved, im just trying to help )

Also... forgive me if im being stupid, but cant you just make formulas with them and then burn them? Surely since oxalates contain 4 oxygen atoms per molecule, then the electrons of the oxygen atoms can be used in a combustion reaction? And a chlorine donor should bring out the colour? At least for strontium and barium anyway...

[cooperman435]

This is all assuming they are Oxalates to begin with :-)