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Hi,
Could anyone help me with instructions on how to make Eriochrome Black T which is used as an indicator in water hardness determinations. The experiment asks for 2 or 3 drops and the only info I can find is add 0.5g indicator to 100g NaCl powder and use 0.2g.
Thanks Tracey

Hi

Make the indicator as follows:

Eriochrome Black-T Indicator. Place 1 gram Eriochrome Black-T and 9 grams of hydroxylamine hydrochloride into a 250-ml glass stock bottle, add 200 ml of reagent grade alcohol, and mix until dissolved. Record the date the indicator is prepared and discard after 3 months.

Kim

Easier methord
Dissolve 1g in 75 ml of commercial Ammonia solution and add 25ml of ethanol.
From Heinemann Chem Prac Manual