The $C - C$ bond length in benzene lies between a single and a double bond. The reason is:

Draw the resonating structures of $(A)$ Ozone molecule $(O_3)$ and $(B)$ Nitrate ion $(NO_3^-)$.

With respect to resonance structures of $CO_3^{2-}$ ion, which of the following statements are correct?
$(a)$ All $C – O$ bonds in $CO_3^{2-}$ are equivalent
$(b)$ There are three resonance structures possible for $CO_3^{2-}$ ion
$(c)$ The position of carbon and oxygen should change in every resonance structure
$(d)$ The formal charge on carbon atom is $0$

During the formation of the dimer $N_2O_4$ from two molecules of $NO_2$,the odd electron on the nitrogen atom of each $NO_2$ molecule pairs up. What is the resulting structure?

The stability order of the following resonance structures is:
$I. CH_2=CH-CH=O$
$II. CH_2^+-CH=CH-O^-$
$III. CH_2^--CH=CH-O^+$

The two bonds $N=O$ and $N-O$ in $CH_3NO_2$ have the same bond length due to: