The enthalpy changes for the following processes are listed below :
Cl₂(g) = 2Cl(g), 242.3 kJ mol^–1
I₂(g) = 2I(g), 151.0 kJ mol^–1
ICl(g) = I(g) + Cl(g), 211.3 kJ mol^–1
I₂(s) = I₂(g), 62.76 kJ mol^–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 :