At 375K and at a total pressure of one atmosphere sulphuryl chloride $\left({\mathrm{SO}}_2,\mathrm{Cl}\right)$ undergoes dissociation according to the equation : ${\mathrm{SO}}_2{\mathrm{Cl}}_2\left(\mathrm{g}\right)\rightleftarrows {\mathrm{SO}}_2\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$ to the extent of 90%. Hence the work done in the process at the same temperature: