In a closed flask at 600 K , one mole of $\mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g})$ attains equilibrium as given below :
$\mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g}) \mathrm{f} \quad 2 \mathrm{XY}_2(\mathrm{~g})$
At equilibrium, $75 \% \mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g})$ was dissociated and the total pressure is 1 atm . The magnitude of $\Delta_{\mathrm{r}} \mathrm{G}^{!}$(in $\mathrm{kJmol}^{-1}$ ) at this temperature is $\_\_\_\_$ . (Nearest Integer)
(Given: $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} ; \ln 10=2.3, \log 2=0.3, \log 3=0.48, \log 5=0.69, \log 7=0.84$ )