Calculate the enthalpy change for the isomerization reaction as given :

${\mathrm{CH}}_2=\mathrm{CH}-{\mathrm{CH}}_2-\underset{\left(\mathrm{A}\right)}{\mathrm{CH}}=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$$\underset{\mathrm{\Delta }}{\stackrel{{\mathrm{NaNH}}_2}{⟶}}{\mathrm{CH}}_2=\mathrm{CH}-\underset{\left(\mathrm{B}\right)}{\mathrm{CH}}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_3$

Use the following data :

${\mathrm{\Delta H}}_{\mathrm{f}}^{\circ }\left({\mathrm{C}}_2{\mathrm{H}}_4\right)=-2275.5\mathrm{kJ}/\mathrm{mol}$

${\mathrm{\Delta H}}_{\mathrm{f}}^{\circ }\left({\mathrm{C}}_2{\mathrm{H}}_6\right)=-2839.2\mathrm{kJ}/\mathrm{mol}$

Resonance energy of A = 50 kJ/mol 

Resonance energy of B = 70 kJ/mol