The reaction, depending on the conditions, is:
(H2N)2CO ---> NH3 + HNCO
The test you describe sounds like the biuret test for the peptide link. Both, urea and proteins have peptide links and give a positive test. If you have done this experiment, you should know the characteristic color.
Biuret is one of the thermal decomposition products of urea. Also, an impurity in urea. How pure was the urea used?
I highly recommend you study the materials related to this experiment. We can't "second guess" from afar what happened where you are.
Urea is heated in a test tube. A condensation reaction occurs.
Which one?
What is the formula for this reaction?
Then cupper sulphate and sodium hydroxide is added to the tube. This is compared to a tube in which cupper sulphate, sodium hydroxide and a solution of egg white are mixed.
What color does it turn into?
Which part of the protein molecule gives the characteristic color with cupper ions in a basic solution?
1 answer
1 answer