Chapter 4, Problem 4.10E

What is the maximum amount of non- $pV$ work that can be done by the reaction

${\text{2H}}_{\text{2}}+{\text{O}}_{\text{2}}\to 2{\text{H}}_{\text{2}}\text{O}$

If ${\Delta }_{\text{f}}G\left({\text{H}}_{\text{2}}\text{O}\right)=-237.13\text{kJ}/\text{mol}$, and ${\Delta }_{\text{f}}G\left({\text{H}}_{\text{2}}\right)={\Delta }_{\text{f}}G\left({\text{O}}_{\text{2}}\right)=0$?