pgadsby at care6.physio-control
Tue Apr 16 13:46:39 EST 1996
In article <3172BAF2.55A4 at primenet.com>, <estherc at primenet.com> writes:
> From: Esther Ceren <estherc at primenet.com>
> Newsgroups: bionet.general
> Subject: pH indicator
> I am looking for the name of the chemical/pigment that changes it's
> color from blue to red in the presence of an acid and to green in the
> presence of an alkali.
You are probably talking about a mixture as opposed to a single indicator.
From the Chem Physics Handbook52nd edition page d-106
Lacmoid changes from red to blue at 4.4 - 6.2
m-Nitrophenol changes from colorless to yellow from 6.8 - 8.6
That should give you what you want.
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