Draw the resonance structures of the following compounds.
$(a)$ $CH_2=CH-Cl:$
$(b)$ $CH_2=CH-CH=CH_2$
$(c)$ $CH_2=CH-CHO$

In a benzene molecule,all $C-C$ bond lengths are equal because:

Given that:
$(i) \Delta_f H^o$ of $N_2O$ is $82 \ kJ \ mol^{-1}$
$(ii)$ Bond energies of $N \equiv N, N = N, O = O$ and $N = O$ are $946, 418, 498$ and $607 \ kJ \ mol^{-1}$ respectively.
The resonance energy of $N_2O$ is $...... \ kJ \ mol^{-1}$.

Given below are two statements :
Statement $I$ : Experimentally determined oxygen-oxygen bond lengths in the $O_3$ are found to be same and the bond length is greater than that of a $O=O$ (double bond) but less than that of a single $(O-O)$ bond.
Statement $II$ : The strong lone pair-lone pair repulsion between oxygen atoms is solely responsible for the fact that the bond length in ozone is smaller than that of a double bond $(O=O)$ but more than that of a single bond $(O-O)$.
In the light of the above statements,choose the correct answer from the options given below:

Select the correct statement about $HCO_3^-$:

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