An ideal gas expands isothermally and reversibly from state ‘A’ (5 litres, 20 atm) to state ‘B’ (50 litres and 2 atm). Work done during the process is 

$\begin{array}{l}{\mathrm{W}}_{\mathrm{rev}}=-2.303 \mathrm{nRT} \log \frac{{\mathrm{V}}_{\mathrm{f}}}{{\mathrm{V}}_{\mathrm{i}}}\\ \mathrm{For} \mathrm{an} \mathrm{ideal} \mathrm{gas}, \mathrm{PV}=\mathrm{nRT}\\ {\mathrm{W}}_{\mathrm{rev}}=-2.303 \mathrm{PV} \log \frac{{\mathrm{V}}_{\mathrm{f}}}{{\mathrm{V}}_{\mathrm{i}}}\\ {\mathrm{W}}_{\mathrm{rev}}=-2.303 \left(100\right) \log \frac{50}{5}\\ {\mathrm{W}}_{\mathrm{rev}}=-230.3 \mathrm{lit}-\mathrm{atm}\\ \mathbf{1}\mathbf{ }\mathbf{lit}\mathbf{-}\mathbf{atm}\mathbf{ }\mathbf{=}\mathbf{101}\mathbf{ }\mathbf{J}\\ {\mathrm{W}}_{\mathrm{rev}}=-230.3\left(101\right) \mathrm{Joules}\\ {\mathrm{W}}_{\mathrm{rev}}=-23.26 \mathrm{kJ}\end{array}$