In a Biuret test , some protein was mixed with sodium hydroxide solution. Which of the following chemicals should be added to the mixture for a positive res...

In a Biuret test , some protein was mixed with sodium hydroxide solution. Which of the following chemicals should be added to the mixture for a positive result?

Answer Details

To conduct a Biuret test, after adding sodium hydroxide to the protein solution, copper sulphate should be added to the mixture for a positive result. This is because the Biuret test is a colorimetric test used to detect peptide bonds in proteins. When copper (II) ions react with peptide bonds in an alkaline solution, a complex is formed that results in a violet or purple color. Therefore, the presence of copper sulphate in the protein-sodium hydroxide mixture is necessary for the test to detect the presence of protein.