Chemistry - Thermodynamics - II Question with Solution | TestHub

$$\begin{array}{rl}& \Delta {\mathrm{G}}_{\mathrm{rxn}}^{\mathrm{o}}={\Delta }_{\mathrm{f}}{\mathrm{G}}^{\circ }\text{ (vapour) }-{\Delta }_{\mathrm{f}}{\mathrm{G}}^{\circ }\text{ (liquid) }\\ & \Delta {\mathrm{G}}_{\mathrm{rxn}}^{\mathrm{o}}=103-100.7=2.3\mathrm{kcal}/\mathrm{mol}\\ & =2300\mathrm{cal}/\mathrm{mol}\\ & \Delta {\mathrm{G}}_{\mathrm{rxn}}^{\mathrm{o}}=-\mathrm{RT}\ln \mathrm{K}\\ & 2300\mathrm{cal}/\mathrm{mol}=-2\mathrm{cal}/\mathrm{mol}\mathrm{K}\times 500\mathrm{K}\times \ln \mathrm{K}\\ & \ln \mathrm{K}=2.3\\ & \mathrm{K}=10\mathrm{atm}=\text{ Vapour pressure of liquid ’ }\mathrm{S}\text{ ’ }\end{array}$$ $\therefore$ Vapour pressure of liquid ' $\mathrm{S}$ ' at $500\mathrm{K}$ is approximately equal to $10\mathrm{atm}$.