Chemistry - Thermodynamics - II Question with Solution | TestHub

(i) $2{\mathrm{Fe}}_2{\mathrm{O}}_3(\mathrm{s})\to 4\mathrm{Fe}(\mathrm{s})+3{\mathrm{O}}_2(\mathrm{g})$; ${\Delta }_{\mathrm{r}}{\mathrm{G}}^{\circ }=+1487.0\mathrm{kJ}{\mathrm{mol}}^{-1}$ (ii) $2\mathrm{CO}(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})\to 2{\mathrm{CO}}_2$ (g) ${\Delta }_{\mathrm{r}}{\mathrm{G}}^{\circ }=-514.4\mathrm{kJ}{\mathrm{mol}}^{-1}$ Multiple reaction (ii) with 3 , we get (iii) $6\mathrm{CO}(\mathrm{g})+3{\mathrm{O}}_2(\mathrm{g})\to 6{\mathrm{CO}}_2(\mathrm{g})$; ${\Delta }_{\mathrm{r}}{\mathrm{G}}^{\circ }=3\times -514.4=-1543.2{\mathrm{kJmol}}^{-1}$ When we add reaction (i) and reaction (iii), we get reaction (iv) (iv) $2{\mathrm{Fe}}_2{\mathrm{O}}_3(\mathrm{s})+6\mathrm{CO}(\mathrm{g})⟶$ $4\mathrm{Fe}(\mathrm{s})+6{\mathrm{CO}}_2(\mathrm{g})$ Free energy change, ${\Delta }_r{G}^{\circ }$ for the reaction will be $$1487.0-1543.2=-56.2\mathrm{kJ}{\mathrm{mol}}^{-1}$$