I was given two bottles with indicators. One bottle contains 10 grams of "Pyrogallol red" indicator and the other bottle contains 25 grams of "tiron
indicator". The pyrogallol red is a dark brown/black compound. The tiron is an off-white compound.
What are these indicators used for? I googled a little and found something about complex-titration, but if one of you has experience/knowledge about
these indicators, then I would be pleased if that could be shared.
I had these bottles (original package/unopened) from an old closed lab in the former GDR (East-Germany).
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