Re: Gum Green

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From: Katharine Thayer (kthayer@pacifier.com)
Date: 05/19/01-11:14:34 AM Z


Judy Seigel wrote:
> ..
>
> But I have read (either on this list or from authorities "met" on this
> list), assurances that our process leaves the dichromate in its TRIVALENT
> form already. Which is (some of) what I mean about lack of confidence in
> "advice" given.
>

Where reduction is completed, dichromate is trivalent, but since only a
small amount of the dichromate is used in order to oxidize the gum
sufficiently to harden it, (Kosar, 1965) most of the dichromate is still
in the hexavalent stage. All that yellow-orange in the water is
hexavalent. Only what's green is trivalent.

Katharine Thayer


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