# How are Pauling's rules applied to Nitric acid?

The Lewis structure of nitric acid is:

So, since Pauling's rule is $\mathrm{p}K_\mathrm{a}=8-5p$, where $p$ is the number of oxo groups, how is the rule applied in this instance? $p=1.5$? $p=2$?

• Have you tried looking at its $\mathrm{pK_a}$? What about comparing it with the $\mathrm{pK_a}$ of its less oxygenated congener nitrous acid, $\ce{HNO2}$? – Nicolau Saker Neto Apr 21 '15 at 20:56
• Both oxygens count as oxo - it doesn't matter how they are bonded but that they stabilise charge of anion counts. – Mithoron Jun 18 '15 at 15:47