At $25^{\circ} \mathrm{C}, 50 \mathrm{~g}$ of iron reacts with HCl to form $\mathrm{FeCl}_2$. The evolved hydrogen gas expands against a constant pressure of 1 bar. The work done by the gas during this expansion is $\_\_\_\_$ J. (Round off to the Nearest Integer) [Given : $\mathrm{R}=8.314 \mathrm{~J}$ mol-1 $\mathrm{K}-1$. Assume, hydrogen is an ideal gas] [Atomic mass off Fe is 55.85 u ]