Each of the structure below represents a planar compound that has resonance form available with cyclic arrangements of  π - electrons. Which compound will be most destabilized because of participation of that resonance structure in the description of compound?

Which of the following structures are aromatic in nature?

With respect to the compounds $\mathrm{I}-\mathrm{V}$ choose the correct statement(s).

The increasing basicity order of the following compounds is:

Which compound amongst the following is not an aromatic compound?

Among the following sets, the most stable ionic species are