The enthalpy changes for the following processes are listed below:
Cl2(g)−2Cl(g),242.3kJmol−1
I2(g)−2I(g),151.0kJmol−1
ICI(g)−I(g)+Cl(g),211.3kLmol−1
I2(s)−I2(g),62.75kJmol−1
Given that the standard states for iodine and chlorine are I2(s) and Cl2(g), the standard enthalpy of formation for ICI(g) is: