Question

which of the following is/are the most significant resonance structure(s) (which contributes the most the overall resonance hybrid)? a. i b. ii c. iii d. all contribute equally to the overall resonance hybrid

Explanation:

The most significant resonance structure has the least separation of formal charges and satisfies the octet rule for as many atoms as possible. Structure I has the positive charge on a more electronegative nitrogen atom compared to III where the positive charge is on a less - electronegative carbon. Structure II has a more stable distribution of charges with the positive charge delocalized in a way that maintains the aromaticity of the benzene - like ring system and has more resonance stabilization.

Answer:

B. II