For the reaction, X(s) $$\rightleftharpoons$$ Y(s) + Z(g), the plot of $\ln {{pz} \over {{p^\theta }}}$ versus ${{{{10}^4}} \over T}$ is given below (in solid line), where pz is the pressure (in bar) of the gas Z at temperature T and ${{p^\theta }}$ = 1 bar. (Given, $${{d(\ln K)} \over {d\left( {{1 \over T}} \right)}} = - {{\Delta {H^\theta }} \over R}$$, where the equilibrium constant, $K = {{pz} \over {{p^\theta }}}$ and the gas constant, R = 8.314 J K $-$ 1 mol $-$ 1)The value of $\Delta$ S $\theta$ (in J K $-$ 1 mol $-$ 1) for the given reaction, at 1000 K is $\underline{\hspace{2cm}}$.