Question

Proteins when heated with conc. HNO₃ give a yellow colour. This is

[CPMT 1989]

• A. Oxidising test
• B. Xanthoprotic test
• C. Hoppe's test
• D. Acid-base test

Answer 1

The correct option is B

Xanthoprotic test

Protein + conc.HNO₃ (r) Yellow colour

[This test is given by a protein which consists of a-amino acids containing a benzene ring such as tyrosine, phenylalanine etc. The yellow colour is due to nitration of benzene ring.]