If values of ΔHof of ICl(g),Cl(g),I(g) are respectively 17.57,121.34,106.96 J mol −1. The value of I−Cl (bond energy) in J mol −1 is:
If S0 for H2, Cl2 and HCL are 0.13, 0.22 and 0.19 kJK-1mol-1 respectively. The total change in standard entropy for th2e reaction, H2+Cl2→2HCl