Question

The correct stability order of the following resonance structures is:

$\underset{\left(I\right)}{H_{2}C=\stackrel{+}{N}=\stackrel{-}{N}}$ $\underset{\left(II\right)}{H_2\stackrel{+}{C}-N=\stackrel{-}{N}}$ $\underset{\left(III\right)}{H_2\stackrel{-}{C}-\stackrel{+}{N}\equiv N}$ $\underset{\left(IV\right)}{H_2\stackrel{-}{C}-N=\stackrel{+}{N}}$

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

Answer 1

The correct option is B $\left(I\right)>\left(III\right)>\left(II\right)>\left(IV\right)$

The resonating structure is more stable if it requires lesser charge separation and the more electronegative atom carries negative charge.

So, the correct stability order of the given resonance structures is $\left(I\right)>\left(III\right)>\left(II\right)>\left(IV\right)$.

Hence, Option "B" is the correct answer.