[pcm81]

I bought some metallic iodine on ebay and would like to know purity of it. Can someone suggest a titration procedure to test for purity?
I have access to standardized KHP, standardized Oxalic acid, standardized KMNO4, which i use to test for iron content. Naturally i can also use those to make a standard NaOH and transfer standard to other acids / bases etc...

One thing that i am concerned with is presence of other metals mixed into the iodine i purchased.

Thanks ahead

[pcm81]

I'd guess that if the sample is contaminated by other metals i'd have to titrate for redox, but currently i do not have an ORP meter. Is there a way to test it without building ORP curve and searching for critical points? Or is searching for multiple "knees" of ORP curve the only way?

[Borek]

1. No such thing as metallic iodine.

2. It would be quite difficult to contaminate elemental iodine with metals.

Look at http://www.titrations.info/iodometric-titration - while it doesn't directly answer the question about the titration method it lists several ways of standardizing iodine, you can be able to adapt one of them.

[pcm81]

1. No such thing as metallic iodine.

2. It would be quite difficult to contaminate elemental iodine with metals.

Look at http://www.titrations.info/iodometric-titration - while it doesn't directly answer the question about the titration method it lists several ways of standardizing iodine, you can be able to adapt one of them.

Well, it does not ship in in a pressurized bottle as a gas, so it has to be metal... Just like Carbon. LOL, just kidding. You're right, i was wrong about calling it a metallic iodine, should have said elemental iodine.

I intend to store it for making iodine solution in case of zombie apocalypse (when i cant actually buy iodine solution). I have lab grade potassium iodide from decent source, and bought elemental iodine on ebay from Russia... Just want to make sure it does not have other crap mixed in with it.

[pcm81]

What i am about to suggest may be royally stupid, so feel free to hit me over the head with something:

I can make a solution of potassium iodine and this supposedly pure elemental iodine. with known quantities of potassium iodide and iodine.
Then use standardized solution of oxalic acid and titrate recording the ORP curve (i need to buy ORP probe to be able to do this)
Based on the critical points that i get on the titration curve i should be able to see if iodine is the only oxidizing agent there or of thee are others.

I guess i can also titrate with KMnO4 to see if i get a single knee or multiple knees to test for stronger oxidizers.

Would this work or am i simply wrong?

Thanks ahead

[Borek]

I believe elemental iodine is purified by sublimation, so it contains very minute amounts of impurities. My gut feeling is that you won't able to determine content of the pure iodine in the sample with accuracy high enough to even approximately estimate amount of impurities (say, you get 99.8%±0.5 - does it tell you anything? And 0.5% is a rather generous assumption when it comes to titration involving iodine, even weighing it is not trivial because of the fast sublimation).

[Enthalpy]

I hope you don't plan to swallow iodine in case of catastrophe?
In case you want stable iodine to ingest in an emergency, you need an iodine compound, like KI, NaI or a mix of both.