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Old phenolphthalein
Posted: 03 Aug 2015, 12:55
by mazcheck
Apparently some bottles of phenolphthalein solution did not work in a titration prac so I was wondering how do you test whether phenolphthalein is good or not?
Re: Old phenolphthalein
Posted: 03 Aug 2015, 13:24
by mtg
I would do an indicator test with a little bit, I've never heard of the solid going off, but the solutions can get mixed up or over diluted. I test them in a bit of NaOH.
Re: Old phenolphthalein
Posted: 03 Aug 2015, 13:47
by rae
You sure it was the phenolphthalein and not operator error. Maybe they added acid to acid.