Identify the major product formed in the following sequence of reactions:

A primary aliphatic amine on reaction with nitrous acid in cold (273 K) and there after raising temperature of reaction mixture to room temperature (298 K), gives a/an

Stability of $$\alpha$$-Helix structure of proteins depends upon

The formula of the purple colour formed in Laissaigne's test for sulphur using sodium nitroprusside is :