----- Original Message -----

From: List Moderator

To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU

Sent: Friday, September 25, 2009 11:08 AM

Subject: Re: [DCHAS-L] Iodine corrosivity

From: Wayne Wolsey <wolsey**At_Symbol_Here**macalester.edu>

Subject: Re: [DCHAS-L] Iodine corrosivity

Date: September 24, 2009 4:09:29 PM EDT

If the metal trap is galvanized iron, meaning zinc-coated, certainly zinc will react spontaneously with I2 in a redox reaction giving Zn2+ and iodide, I- .  The same thing can happen with aluminum, with similar chemistry.

Wayne Wolsey

Professor Emeritus

Macalester College

St. Paul, MN

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From: Ernest Lippert <ernielippert**At_Symbol_Here**toast.net>

Subject: Re: [DCHAS-L] Iodine corrosivity

Date: September 24, 2009 5:39:12 PM EDT

Linda,

Based on the observed results, elemental iodine will corrode a metal trap. A knowledge of basic descriptive chemistry, as it was once taught, bears this out. There are a couple of things wrong here, not the least of which was an incorrect disposal method. A plumber should have been called to remove and clean the trap. His visit would be followed by proper disposal of the residue. If this couldn't have been done and as a last effort, the teacher perhaps should have known that iodine is much more soluble in a solution of potassium iodide than in water. On the other hand, is it preferable to have a leak with its obvious local contamination followed by proper disposal of the residues than it is to discharge a (significant) amount of iodine and KI into the sewer system?

Regards,

Ernest Lippert

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From: Robert Weeks <rweeks**At_Symbol_Here**lanl.gov>

Subject: Re: [DCHAS-L] Iodine corrosivity

Date: September 25, 2009 10:57:28 AM EDT

Certainly a possibility. Might be interesting to perform  surogate experiments w/iodine crystals and pieces of pipe metal. Do the experiment w/iodine crystals, w/whatever else might have gone down this drain, and then w/iodine crystals plus whatever else might have gone down the drain.

Bob