Chemistry Anion/cation testing

[D'Nalor]

I've got a chemistry practical exam, and in preparation for it, we have to devise tests for certain anions/cations. I need a bit of help for the Nitrate Ion (NO₃^-. is there any test that you can perform on nitrate to get a distinctive reaction? precipitation reactions are out, any Cations that might cause a precipitate to form would be unavilable in a school laboratory. is there any easy test? otherwise, I might just have to hope it isn't on the exam. I'm hoping to use the acetate ion when possible too so it won't interfere with any other things i'm testing for(because it's soluble with everything listed in my textbook, and so makes a good carrier ion)

Other thing, for the cations, I need to add Hydroxide ions (OH^- to the solution (to remove copper, iron, zinc, etc.), but later I need to flame test for sodium, potassium, barium, stromium, etc. basicly, all the ions that actually dissolve in water when they're with hydroxide. my textbook doesn't actually show lots of the tests that you could use, so if there are any easy ones that would work, I'd like to know them.

[John Cuthber]

http://en.wikipedia.org/wiki/Devarda's_alloy.

 

how much stuff do you get to analyse?

How much does it take to do these reactions?

[D'Nalor]

Anions to test for: S^2-, OH^-, SO₃^2-, SO₄^2-, NO₃^-, Cl^- and CO₃^2-

 

Cations to test for: Iron (II), Iron (III), Copper (II), Lead (II), Stromium, Calcium, Sodium, Pottassium, Aluminium (III), Barium, Silver (I), Zinc (II) and magnesium.

 

I have no idea how much we'll be allowed, but I should immagine as much as we need. Not sure of the concentrations, but they should be about .1 M. If it's any guide, about 5 drops(not very acurate, I know) is usually enought to get a distinctive reaction.

 

Devarda's alloy... sounds as if it would be usefull. I'm assuming that the reaction would cause ammonia gas, which would make it distinctive, the article didn't state the states of the matter. following a link from the page, there's another test that would work. thanks for that.

Edited October 22, 2010 by D'Nalor

[Horza2002]

Colour would be the easiest way to determin the identity of many of the metal ions. And a flame test should help you with the likes of sodium, calcium, potassium and barium that don;t have a colour.