Question

Question #fad67

Answer 1

`OH + NO_2 -> HNO_3`

Explanation:

While the origin of nitrous acid can still not be explained satisfactorily, recent experimental results show that besides the formation of `HNO_3` via OH reactions, nitrate radicals (`NO_3`) can initiate a reaction sequence of comparable efficiency.
https://link.springer.com/chapter/10.1007/978-3-642-70627-1_12

Other references:
https://www.osti.gov/scitech/biblio/6029056