Question

If you touch concentrated ${HNO_3}$ with your finger and immediately wash it with water, then the skin at the place where it came into contact with ${HNO_3}$ becomes yellow. This is because of :

• A. the formation of Xanthoprotein
• B. the absorption of $\ce{HNO_3}$ by skin
• C. the blood absorbing $\ce{HNO_3}$
• D. the absorption of yellow/brown $\ce{NO_2}$ gas

Answer 1

Answer: (A)

the formation of Xanthoprotein

Answer 2

Nitric acid attacks proteins forming a yellow nitro compound called xanthoprotein. It therefore, stains skin and renders wool yellow. This property is utilised for the test of proteins.