Chemistry - GOC Question with Solution | TestHub

A is pyridine, which is aromatic (P), heterocyclic (R) and contains an odd number of σ-bonds (T).

B is cyclopentadiene, so it is non-aromatic (Q), has an even number of π-bonds (S) and odd number of σ-bonds (T).

C is protonated pyrrole, hence non-aromatic (Q), heterocyclic (R), with even π-bonds (S) and odd σ-bonds (T).

D is naphthalene, which is aromatic (P) and has an odd number of σ-bonds (T).

Therefore, the correct matching is:

A → PRT;B → QST;C → QRST;D → PT