Question

The correct stability order of the following resonating structures is:

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

• A. I > II > IV > III
• B. I > III > II > IV
• C. II > I > III > IV
• D. III > I > IV > II

Answer 1

The correct option is B I > III > II > IV

In (I) and (III) octet is complete for all the atoms so they are more stable than (II) and (IV).
In (I) negative charge is on more electronegative element so it is more stable than (III).
In (II) –ve charge is on more electronegative element and +ve charge is on less electronegative element so it is more stable than (IV).