The enthalpy changes for the following processes are listed below : <br> $Cl_2 (g) = 2Cl (g), \; \; \; 242.3 \; kJ\; mol^{-1} $ <br> $I_2 (g) = 2I (g), \; \; \; 151.0 \; kJ\; mol^{-1} $ <br> $ICl (g) = I (g) + Cl(g), \; \; \; 211.3 \; kJ\; mol^{-1}$ <br> $I_2 (s) = I_2 (g), \; \; \; 62.76 \; kJ\; mol^{-1}$ <br> Given that the standard states for iodine and chlorine are $I_2 (s)$ and $Cl_2 (g)$, the standard enthalpy of formation of $ICl \; (g)$ is :
