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

A gas absorbs $$150 \mathrm{~J}$$ heat and expands by $$300 \mathrm{~cm}^3$$ against a constant external pressure $$2 \times 10^5 \mathrm{~N} \mathrm{~m}^{-2}$$, What is $$\Delta \mathrm{U}$$ of the system?

Equal masses in grams of $$\mathrm{H}_2, \mathrm{~N}_2, \mathrm{Cl}_2$$, and $$\mathrm{O}_2$$, are enclosed in cylinders separately. If these gases expand isothermally and reversibly by $$10 \mathrm{~dm}^3$$ at $$300 \mathrm{~K}$$, the work done by gas is maximum for

If lattice enthalpy and hydration enthalpy of $$\mathrm{KCl}$$ are $$699 \mathrm{~kJ} \mathrm{~mol}^{-1}$$ and $$-681.8 \mathrm{~kJ} \mathrm{~mol}^{-1}$$ respectively. What is the enthalpy of solution of $$\mathrm{KCl}$$ ?