: An aromatic amine reacts with nitrous acid at low temperatures to form a diazonium salt .
The synthesis of these dyes usually involves a two-step process: azo dye
: The diazonium salt acts as an electrophile, reacting with an electron-rich nucleophile (like a phenol or another aromatic amine) to create the final azo bond. Industrial and Biological Applications : An aromatic amine reacts with nitrous acid