${H_2}C = C{H_2}(g) + {H_2}(g) \to {H_3}C - C{H_3}(g)$
\(435 \times 1\,\,\, = \,\mathop {435}\limits_{\overline {\underline {2706} } } \)
\(\Delta H = 2706 - 2831 = - 125\,kJ\)
(Given ${\Delta _{fus}}H = 6\, kJ\, mol^{-1}$ at $0\,^oC$,
$C_p(H_2O, l) =75.3\, J\, mol^{-1} \, K^{-1}$ ,
$C_p(H_2O, s) = 36.8\, J\, mol^{-1} \, K^{ -1}$ )
| $H - H$ બંધઊર્જા | $:\, 431.37 \,kJ\, mol^{-1}$ |
| $C= C$ બંધઊર્જા | $:\, 606.10\, kJ \,mol^{-1}$ |
| $C - C$ બંધઊર્જા | $:\, 336.49\, kJ\, mol^{-1}$ |
| $C - H$ બંધઊર્જા | $:\, 410.50\, kJ\, mol^{-1}$ |
પ્રક્રિયા : $\begin{array}{*{20}{c}}
{H\,\,\,\,H} \\
{|\,\,\,\,\,\,\,\,|} \\
{C = C} \\
{|\,\,\,\,\,\,\,\,\,|} \\
{H\,\,\,\,H}
\end{array}\, + \,H - H\, \to \,\begin{array}{*{20}{c}}
{H\,\,\,\,H} \\
{|\,\,\,\,\,\,\,\,|} \\
{H - C - C - H} \\
{|\,\,\,\,\,\,\,\,\,|} \\
{H\,\,\,\,H}
\end{array}\,$