${\mathrm{NCl}}_5$ does not exist while ${\mathrm{PCl}}_5$ does because nitrogen does not have vacant $\mathrm{d}$ orbitals while phosphorous contains $\mathrm{d}$ orbitals.

$\mathrm{Pb}$ shows the inert pair effect, due to this most of the lead compounds are divalent not tetravalent.

All the bonds of ${{\mathrm{CO}}_3}^{2-}$ are equal due to resonance effect.

Both ${\mathrm{O}}_2^{+}$ and $\mathrm{NO}$ are paramagnetic due to the presence of unpaired electrons in their molecular orbitals.

Hence, option $\mathrm{B}$ is not correct