At 25^oC the enthalpy of the following processes are given:
$\begin{array}{l}{\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{OH}\left(\mathrm{g}\right){\mathrm{\Delta H}}^{\circ }=78\mathrm{kJ}{\mathrm{mol}}^{-1}\\ {\mathrm{H}}_2\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right){\mathrm{\Delta H}}^{\circ }=-2.42\mathrm{kJ}{\mathrm{mol}}^1\\ {\mathrm{H}}_2\left(\mathrm{g}\right)\to 2\mathrm{H}\left(\mathrm{g}\right){\mathrm{\Delta H}}^{\circ }=436\mathrm{kJ}{\mathrm{mol}}^{-1}\\ \frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)\to \mathrm{O}\left(\mathrm{g}\right){\mathrm{\Delta H}}^{\circ }=249\mathrm{kJ}{\mathrm{mol}}^{-1}\end{array}$
What would be the value of X for the following reaction? ________________
(Nearest integer)
${\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\to \mathrm{H}\left(\mathrm{g}\right)+\mathrm{OH}\left(\mathrm{g}\right){\mathrm{\Delta H}}^{\circ }=\mathrm{XkJ}{\mathrm{mol}}^{-1}$