Question

What is the formal charge of N in `HNO_3`?

Answer 1

`"Nitrogen has a formal +1 charge."`

Explanation:

A reasonable Lewis structure is `H-O-stackrel(+)N(=O)O^-`. One of the oxygen atoms has a formal negative charge, and the nitrogen atom is quaternized and bears a formal positive charge. Of course, the molecule is neutral, and the Lewis structure reflects this.

Note that when nitric acid dissociates:

`HNO_3(aq) + H_2O(l) rarr H_3O^+ + NO_3^-`

There are 3 formal charges on the nitrate ion: `""^(-)O-stackrel(+)N(=O)-O^-`. The overall charge on the ion is still `-1`, but there is again formal charge separation in our representation of the anion.