220 PHYSIOLOGICAL CHEMISTRY 



4. Nitric Acid Test. Add some nitric acid to some of the material under 

 examination. Heat and note a yellow color due to the production of picric acid 

 (trinitrophenol) from phenol. This is the reaction : 



Phenol. Picric acid. 



Tests for Oxyacids 



1. Color Test. Test a little of the solution with Millon's reagent. A red color 

 results. 



2. Bromine Water Test. Add a few drops of bromine water to some of the 

 nitrate. A turbidity or precipitate is observed. 



Test for Skatole -carbonic Acid 



Ferric Chloride Test. Acidify some of the nitrate with hydrochloric acid, add 

 a few drops of ferric chloride solution, and heat. Compare the end-reaction with 

 that given by phenol. 



