Thus, in \(\mathrm{NO}_{3}\), the central atom is \(sp ^2\) hybridized and it has trifocal planar geometry. \(\ln \mathrm{H}_{3} \mathrm{O}^{+}\)

\(\mathrm{H}=\frac{1}{2}[6+3-1+0]=4\)

Thus, \(\mathrm{O}\) is \(s p^{3}\) hybridised in \(\mathrm{H}_{3} \mathrm{O}^{+}\) and \(\mathrm{H}_{3} \mathrm{O}^{+}\) has pyramidal geometry due to the presence of one lone pair of electrons.