(N/A) The following conditions prove the exceptional stability of benzene:
$i$. Benzene resists addition reactions compared to alkenes.
$ii$. Despite having a lower ratio of hydrogen atoms to carbon atoms, benzene readily undergoes electrophilic substitution reactions rather than addition reactions.
$iii$. The bond length in benzene is $139 \ pm$, which is intermediate between the $C-C$ single bond length $(154 \ pm)$ and the $C=C$ double bond length $(133 \ pm)$, indicating delocalization.
$iv$. Benzene has a very low enthalpy of hydrogenation, which is $36 \ kcal \ mol^{-1}$ less than the expected value for a hypothetical cyclohexatriene. This difference represents the resonance energy of benzene.
$v$. Benzene is exceptionally stable due to its aromatic character, which follows Hückel's rule ($4n+2 \ \pi$ electrons).