Identify Nitrates Nitrites

Hello All,
It has been several years since I purchased that big box of white salts, so long ago I am no longer sure if it is KNO3, or KNO2 or NaN... Heck fire I never had a chemistry class, ever. The thing is I bought it to make Nitric Acid for AR and there it has sat for over 5 years. Anyone know how to test for what it actually is ? I suppose I could just use it as fertilizer, ugh somewhat expensive fertilizer, I would rather not.
Thank You for your time.

If you are sure it is potassium or sodium nitrate (NO₃^-) or nitrite (NO₂^-), you can take a piece of wood like the bare end of a safety match,make it wet,stick it into the salt so a tiny littlebit lingers to it and hold it into a flame. sodium will colourize the flame yellow, pure potassium salts will colourize it kind of violett/purple. If it is nitrate it will oxidize the wood with a slightly fizzing sound.

I don't know what will happen to nitrides (N^-)

A common method specific for the testing of the presence of nitrates is the very simple brown ring test. If the salts are nitrites, it won't test positive.

(1) Dissolve a little of the salts in distilled water and add about an inch of this solution to a clean test tube.

(2) Add enough 10% sulfuric acid to acidify the solution.

(3) Make up a fresh solution of ferrous sulfate (copperas) and add about 1/2", or so, of it to to the test tube. It must be freshly made. A gram or so dissolved in 4 or 5 ml of distilled water should work. Mix the solution and if, for some reason, it is hot or warm, allow it to cool to room temp.

(4) Tilt the test tube and slowly add about 1/2" of concentrated sulfuric in a slow steady stream down the side of the test tube with an eyedropper or a pipet. The sulfuric is very heavy and, if you do this properly, it will sink to the bottom and form a separate layer. You don't want the 2 solutions to mix together.

(5) If nitrates are present, a brown or purple/brown ring will form at the junction of the 2 layers.


I've done this many times but it's been about 30 years. I had to look it up. For more details, Google "brown ring test". You can find several videos on this. Here is one:
http://www.youtube.com/watch?v=095QmLQKMCE

The quantities don't seem to be that critical as long as the solution being tested is acidic and you use enough fresh ferrous sulfate. I would first test your procedure with about an inch of water with several drops of nitric acid added. In this case, it's already acidified so no 10% sulfuric will be needed and you can eliminate step (2) above.

Thank You I will try those tips. I bought 20 pounds as it was not super expensive, but enough so I do not wish to waste it. Again, Thanks, Joe