SolutionsNitrosation

NaNO₂ + HCl → HO–N=O + NaCl; HO–N=O + H⁺ ⇌ H₂O⁺–N=O → N≡O⁺ + H₂O.

The nitrosyl cation, NO⁺, is an electrophile: amines attack it with the nitrogen lone pair.

1. N-Nitrosodiethylamine, (CH₃CH₂)₂N–N=O, stable.
2. The propyldiazonium salt, which loses N₂ at once to give a primary carbocation: a mixture of 1-propanol, 2-propanol (by rearrangement), propene and chlorides is formed.
3. An N-nitrosoammonium salt, which does not evolve into a stable neutral product.

Because in the acidic medium of the stomach nitrites form nitrous acid, which converts secondary amines into N-nitrosoamines, carcinogenic compounds.