Which of the following is the correct formula for nitrous acid? a) HNO b) HN2O c) N2O d) HNO2 e) HNO3

d) HNO2

Explanation:

we determine the valence electrons for each substance:

⇒for the Nitrogen, it works with 3 and 5 valence electrons, prefixes are used - oso (for the lower valence), in this case is it for three, and the susbtance where the nitrogen works with this valence is: HNO2.

So the answer is d)