Van't Hoff Equation
This equation gives the quantitative temperature dependence of equilibrium constant (K). The relation between standard free energy change (ΔG°) and equilibrium constant is
Differentiating equation (3) with respect to temperature,
Equation 4 is known as differential form of van’t Hoff equation.
On integrating the equation 4, between T1 and T2 with their respective equilibrium constants K1 and K2.
Equation 5 is known as integrated form of van’t Hoff equation.
For an equilibrium reaction Kp = 0.0260 at 25° C ΔH= 32.4 kJmol-1, calculate Kp at 37° C
T1=25 + 273 = 298 K
T2 = 37 + 273 = 310 K
ΔH = 32.4 KJmol-1 = 32400 Jmol-1
R=8.314 JK-1 mol-1