Q. Proteins when heated with conc. $HNO_{3}$ give a yellow colour. This is
A) Hoppe’s test
B) Acid-base test
C) Biuret’s test
D) Xanthoprotic test
Explanation
(d)
Protein + conc. $HNO_{3}\overset{\ \ \ \ \mathrm{\Delta}\ \ \ \ }{\rightarrow}$ yellow colour
This test is called Xanthoprotic test. It is given by those proteins which consists of $\alpha$- amino acid containing benzene ring $eg.,\ tyrosine$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.