Which of the following processes exhibits increase in internal energy?

One mole of an ideal gas performs $$900 \mathrm{~J}$$ of work on surrounding. If internal energy increases by $$625 \mathrm{~J}$$, find the value of $$\Delta \mathrm{H}$$.

Calculate the work done in the following reaction at $$300 \mathrm{~K}$$ and at constant pressure.

$$\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$$

$$4 \mathrm{HCl}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{Cl}_{2(\mathrm{~g})}+2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{g})}$$

Which among the following is NOT the feature of reversible process?