# Electrophilic substitution of benzene with conc. HNO₃ and HNO₂

The following question was given in my FIITJEE study material:

$$\ce{Benzene + \text{conc.} HNO_3 + HNO_2 ->}$$ Final product of the reaction is:

, , ,

I started with the solution by deciding the Lewis acid out of $$\ce{HNO_3}$$ and $$\ce{HNO_2}$$. I guess $$\ce{HNO_3}$$ should be Lewis acid as O.S. of N is higher in it. Hence, I wrote the reaction to generate electrophile:

$$\ce{HNO_3 + HNO_2 -> NO_3^- + H_2O + NO^+}$$

Now, it is a bit clear who's the electrophile. Hence, I thought that first option would be the final product. But, according to the answer key it was wrong.

What I am doing wrong?

Nitrosyl cation, $$\ce{NO^+}$$, is a better electrophile than molecular $$\ce{HNO3}$$ (you don't get $$\ce{NO_2^+}$$ in this system without sulfuric acid or other strong auxiliary acid) and so you get nitrosobenzene in the substitution reaction. But then the nitrosyl group with its nonbonding electron pair is an attractive target for oxidation by the nitric acid and thereby is converted to $$\ce{NO_2}$$. Thus nitrobenzene. Then, the nitrobenzene, deactivated by the nitro group, will not react with the relatively mild electrophile $$\ce{NO^+}$$ anymore, meaning products C and D are never reached (and their nitrosyl groups would not have survived anyway).