Ferroxyl indicator solution

Corrosion of iron nail with coiled copper in medium with ferroxyl indicator

Ferroxyl indicator is a solution containing potassium ferricyanide and phenolphthalein. It turns blue in the presence of Fe²⁺ ions, pink in the presence of hydroxide ions, and can be used to detect metal oxidation. It is often used to detect rusting in various situations.

It can be prepared by dissolving 10g sodium chloride and 1g potassium hexacyanoferrate(III) in distilled water, adding 10 cm³phenolphthalein indicator, then making up to 500 cm³ with distilled water.^[1]

The solutions must be mixed together and used within 24 hours to get best results. ==References==