Standard entropies of X2, Y₂ and XY₃ are 60, 40 and 50 J K–1 mol–1 respectively. For the reaction 1/2X2 + 3/2Y₂ ⇌ XY₃, ∆H = –30 kJ, to be at equilibrium, the temperature should be (2010)

Given reaction is : 2 2 3 1 3 X Y XY 2 2 THERMODYNAMICS AND THERMOCHEMISTRY 53 We know, o o o products reactants S S S 1 3 50 60 40 2 2 = 50 – (30 + 60) = – 40 J K–1 mol–1 At equilibrium ∆G° = 0 ∆H° = T∆S° o 3 1 o 1 1 H 30 10 J mol T 750K S 40J K mol x