Biuret Test: By slowly heating the urea, ammonia gas comes out and a white solid material is obtained. Which is called Biuret. Ammonia can be identified by its pungent and distinct smell. Purple solution is obtained by adding a few drops of solutions of dilute sodium hydroxide and dilute copper sulphate in aqueous solution of a white solid.
Ammonia is formed by heating urea with a solution of caustic soda, which can be readily identified by its odor.
A white precipitate of urea nitrate or urea oxalate is obtained by adding concentrated nitric acid or concentrated oxalic acid solution to the concentrated solution of urea.
Nitrogen gas is released rapidly by adding sodium nitrite solution by adding dilute hydrochloric acid to the urea solution.
Nitrogen gas is released when alkaline Hypobromite is added to an alkaline solution of urea.