Question

On heating with conc. $H{NO}_3$, proteins give yellow color. This test is called:

• A. oxidising test
• B. xanthoproteic test
• C. Hoppe's test
• D. acid-base test

Answer 1

The correct option is B xanthoproteic test

• Product of xanthoproteic reaction with the characteristic yellow color. The xanthoproteic reaction is a method that can be used to determine the amount of protein soluble in a solution, using concentrated nitric acid. The test gives a positive result in amino acids carrying aromatic groups.
  
• Hence option B is correct answer.