I have two recipes:
potassium hexacyanoferrate(III):
1g of powder dissolve in 100ml water.
Add indicator to a test tube containing test soln. If Fe2+ is present, solution will turn deep blue.
2nd one is used in corrosion exp and contains agar to make a gel. Students pour is over different metals into petri dishes:
100ml hot water, 3g agar powder, 1g sodium chloride and 1ml of 0.5M hexacyanoferrate. Keep warm to prevent setting.
If you need phenolphthalein, just add 0.5g or less but we do not add that to ours.
Hope this will help
lada
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