Resorcinol + FeCl3

Question

Do both OH of resorcinol be substituted with FeCl2 upon reacting with FeCl3 and no excess HCl product? or it will just substitute one of the H in the hydroxyl group plus an HCl product? Need help to resolve my confusions.

Answer 1

Hi, Airah,

I think you're wondering about the ferric chloride test for the identification of phenols, yes? If that's your question, the reaction involves a single hydroxyl of a polyhydroxylated species (such as resorcinol, which has two hydroxyls), so the balanced equation would be:

The resulting ferric salt would be blue (simple phenols with one hydroxyl group form violet products).