Compounds with a phenol group will form a blue, violet, purple, green, or red-brown color upon addition of aqueous ferric chloride. This reaction can be used as a test for phenol groups.
3ArOH + FeCl3 → Fe(OAr)3 + 3HCl
To Conduct Demonstration:
- Mix several drops or a few crystals of compound to be tested in a beaker or in a 200mm test tube.
- Add a few drops of 1% FeCl3.
- As a control, add a few drops of 1% FeCl3 to water in a second beaker. Also, mix aspirin in water to use as a control
- Observe color change, if any.
Gloves are recommended.
D.J. Pasto and C.R. Johnson, Laboratory Text for Organic Chemistry, p 410, 1979.
Margaret Asirvatham, Spring 1992.