Question

The least stable resonating structure of phenol is :

• A. $\left(III\right)$
• B. $\left(I\right)$
• C. $\left(IV\right)$
• D. $\left(II\right)$

Answer 1

The correct option is A $\left(III\right)$

Among the resonating structures of phenol, structure $\left(I\right)$ and $\left(V\right)$ are the most stable due to highest number of covalent bonds.
Structure $\left(III\right)$ is least stable because the separation of unlike charges is highest in the structure.
Therefore, the correct order of stability of resonating structures of phenol is:
$\left(I\right)=\left(V\right)>\left(II\right)=\left(IV\right)>\left(III\right)$