Which pair does not represent a pair of resonance structures?
A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question

Which pair does not represent a pair of resonance structures? 
A)I 
B)II 
C)III 
D)IV 
E)All of these choices represent pairs of resonance structures.

Quizplus · Accepted Answer

Structure IV is not a resonance structure of the others because it has a different atom arrangement, which cannot be represented by delocalization of pi electrons. Therefore, it is not part of the resonance hybrid.

Which Pair Does Not Represent a Pair of Resonance Structures