From: Judy Seigel (email@example.com)
Date: 05/09/01-08:47:57 PM Z
On Wed, 9 May 2001, Sil Horwitz wrote:
> Sorry if I'm longwinded about this, but otherwise I find I
> get many additional questions. Hope I've answered them all in advance.
Ha ha, of course not.... here's another...
True, my chemistry is a bit fuzzy, but if it's something ELSE makes the
dichromate residue turn blue-green, is it possible that a sequestering
agent could prevent that???
(Around here it doesn't do that, but I take the reports as true.)
> ...EDTA has only one main function: it's a sequestering agent. That
> is, it can prevent interaction between two otherwise reactive substances.
> Its main use is in preventing many metals from reacting with others,
> therefore, it is used in photography (and washing compounds) for minimizing
> the effect of calcium in tap water from combining with sulfites and other
> chemicals that form insoluble calcium compounds. Also used in bleach-fix
> solutions to minimize reaction of iron compounds with thiosulfates (fixer)
> which are otherwise incompatible. (Its use in some of the alternative
> processes is highly questionable in value. But if the practitioner feels it
> helps, fine, as it won't hurt!)
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