The enthalpy changes for the reaction
$ \begin{aligned} & \mathrm{H}_{2} \mathrm{O}_{(g)} \longrigh

Question

The enthalpy changes for the reaction 
$ \begin{aligned} & \mathrm{H}_{2} \mathrm{O}_{(g)} \longrightarrow \mathrm{H}_{(g)}+\mathrm{OH}_{(g)} 	ext { and } \ & \mathrm{OH}_{(g)} \longrightarrow \mathrm{O}_{(g)}+\mathrm{H}_{(g)} \end{aligned} $
are $501.87 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $423.38 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The bond enthalpy of $\mathrm{O}-\mathrm{H}$ bond is\

Professor PC Thomas Classes · Answer

(b) :
$
\begin{aligned}
: B E(\mathrm{O}-\mathrm{H}) & =\frac{501.87 \mathrm{~kJ} \mathrm{~mol}^{-1}+423.38 \mathrm{~kJ} \mathrm{~mol}^{-1}}{2} \
& =462.625 \mathrm{~kJ} \mathrm{~mol}^{-1}
\end{aligned}
$