Sciencemadness Discussion Board

Stoichiometry of Iodine Tincture Extraction

nah89 - 18-5-2015 at 18:42

Hi,

I'm planning on doing an extraction of elemental Iodine from Iodine tincture via HCl and H2O2. I googled around and couldn't find the chemical formula for the reaction and I was wondering if you might be able to help me?

Thanks

Zephyr - 18-5-2015 at 18:46

Seems like you missed quite a few resources in your googling...
First resource I found: http://www.sciencemadness.org/talk/viewthread.php?tid=14300
This seems pretty definitive, I hope this helps.
As for the exact reaction, I think the potassium iodide helps hold the iodine in solution IIRC, so when the KI is reacted with the HCl and H2O2 to create hydroiodic acid and potassium chloride, which is subsequently oxidized to iodine and water, the rest of the I2 to precipitates.

[Edited on 5-19-2015 by Pinkhippo11]

j_sum1 - 18-5-2015 at 18:48

Welcome to SM. this has been covered a large number of times.
Forum protocol here is to search first and add to existing thread if you have something to contribute or questions that have not yet been addressed. I suggest you read around the site -- it is lots of fun. Also read the forum faq and enjoy your stay here.

nah89 - 19-5-2015 at 06:52

Thanks! All of those seem to give instruction on how to do it, but they don't give the stoichiometry behind it. I was just hoping to have that in order to find out exactly how much HCl and H202 to add for how much Tincture. Since the reaction is pretty much the single replacement of the anion in the KI, the only reaction needed to know would be that?

Metacelsus - 19-5-2015 at 07:32

2 I- -> I2 + 2 e-
2 H+ + H2O2 + 2 e- -> 2 H2O

nah89 - 19-5-2015 at 14:46

Thanks!