Which from following statements is true about internal energy?

2 moles of an ideal gas are expanded isothermally and reversibly from 20 L to 40 L at 300 K . Calculate work done. ( $\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$).

10 g each of $\mathrm{NH}_3, \mathrm{~N}_2, \mathrm{Cl}_2$ and $\mathrm{H}_2 \mathrm{~S}$ are expanded isothermally and reversibly at same temperature. Identify gas that performs maximum work.

Identify the factor from following on which heat of reaction does not depend.