For a particular reversible reaction at temperature T, ∆H and ∆S were found to be both +ve. If T_e is the temperature at equilibrium, the reaction would be spontaneous when :

The standard enthalpy of formation of NH₃ is –46.0 kJ mol^–1. If the enthalpy of formation of H₂ from its atoms is –436 kJ mol^–1 and that of N2 is –712 kJ mol^–1, the average bond enthalpy of N–H bond in NH₃ is :

On the basis of the following thermochemical data :
($$\Delta _fG^oH^+_{(aq)}$$ = 0)

H₂O(l) $$\to$$ H⁺(aq) + OH^-(aq); $$\Delta H$$ = 57.32 kJ
H₂(g) + $${1 \over 2} O_2(g) \to$$ H₂O(l); $$\Delta H$$ = -286.20 kJ

The value of enthalpy of formation of OH⁻ ion at 25^oC is :

Standard entropy of X₂, Y₂ and XY₃ are 60, 40 and 50 JK⁻¹ mol⁻¹ , respectively. For the reaction,
$${1 \over 2} X_2$$ + $${3 \over 2} Y_2 \to$$ XY₃, $$\Delta H$$ = -30 kJ, to be at equilibrium, the temperature will be :