Question

The correct stability order of the following resonance structure is (I) $H_2C = _{N}^{+} = _{N}^{-} \, \, \, \,$ (II) $H_2 \, _{C}^{+} - N = _{N}^{-}$ (c) $H_2 \, _{C}^{-} - _{N}^{+} = N \, \, \, \,$ (IV) $H_2 {C}^{-} - N = N$

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

Answer 1

Answer: (B)

$(I) > (III) > (II) > (IV)$

Answer 2

I is most stable because it has more covalent bonds and negative
charge on electronegative nitrogen. Ill is more stable than II and
IV due to greater number of covalent bonds. Between II and IV,
II is more stable since, it has negative charge on electronegative
atom and positive charge on electropositive atom. Hence,
overall stability order is
I > III > II > IV