For the synthesis of phosgene,

CHEMISTRY · Multi-part · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

For the synthesis of phosgene, CO(g)+Cl2(g)→COCl2(g)\mathrm{CO}(g) + \mathrm{Cl}_2(g) \rightarrow \mathrm{COCl}_2(g), the standard enthalpy change is ΔH=−92.3 kJ mol−1\Delta H = -92.3\,\text{kJ}\,\text{mol}^{-1} and the standard entropy change is ΔS=−198 J mol−1 K−1\Delta S = -198\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1}. Assume both quantities remain constant with temperature. (1) Part 1: Calculate the temperature (in K\text{K}) at which the reaction is at equilibrium (ΔG=0\Delta G = 0). Show all unit conversions clearly. (2) Part 2: Determine the sign of ΔG\Delta G at 298 K298\,\text{K}. State whether the reaction is thermodynamically favored under standard laboratory conditions and justify your answer. (3) Part 3: Determine the sign of ΔG\Delta G at 1200 K1200\,\text{K}. Explain how the favorability changes compared with part (b). (4) Part 4: Industrial plants often operate this reaction near 350 K350\,\text{K}. Using your results, briefly discuss one advantage of performing the reaction close to, but below, the equilibrium temperature you calculated in part (a).

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