The enthalpy changes for the following processes are listed below:
Cl2(g)⟶2Cl(g);ΔHo=242.3kJmol−1
I2(g)⟶2I(g);ΔHo=151.0kJmol−1
ICl(g)⟶I(g)+Cl(g);ΔHo=211.3kJmol−1
I2(s)⟶I2(g);ΔHo=62.76kJmol−1
Given that the standard states for iodine and chlorine are I2(s) and Cl2(g), the standard enthalpy of formation for ICl(g) is: