The bond enthalpy values of H-H, O=O bonds are 436 kJ/mole and 498 kJ/mole respectively. Standard enthalpy of formation of water is -286 kJ/mole. The bond enthalpy of O-H bond is equal to-----kJ/mole

$\begin{array}{l}\mathrm{H}-\mathrm{H}+\frac{1}{2}\mathrm{O}=\mathrm{O} \to 2\mathrm{O}-\mathrm{H}, \\ \mathrm{H}=-286 \mathrm{kJ} ;+436+\frac{1}{2}\left(498\right) +\left(-2\mathrm{x}\right) =-286 ; \\ \mathrm{x}=\frac{436+249+286}{2} \\ \mathrm{x}=485.5 \mathrm{kJ} ; \\ \mathrm{O}-\mathrm{H} \mathrm{bond} \mathrm{enthalpy}=485.5 \mathrm{kJ}/\mathrm{mole} ;\end{array}$