Consider the following three resonance structures:
The correct order of their stabilities is:

Which of the following pairs does not represent resonating structures?

In benzene, why is neither of the two given resonance structures considered to be the correct representation of the actual molecule?

The resonance energy of the following heterocycles is in the order:

Draw the possible resonance structures for $CH_3 - \ddot{O} - CH_2^+$ and predict which of the structures is more stable. Give reason for your answer.

Identify the relationship between the following two structures: $\begin{matrix} \overset{\Theta}{\overset{\centerdot \,\centerdot}{C}}H_2-C(=O)-CH_3 \end{matrix}$ and $\begin{matrix} CH_2=C(O^{\Theta})CH_3 \end{matrix}$