If ΔfH⊖ofICl(g),Cl(g),andI(g)is17.57,121.34and106.96J−1, respectively. Then bond dissociation energy of I-Cl bond is:
Bond dissociation energy =2×ΔHf of ICl(g)
Hence DE=2×17.57 J−1
DE=35.15 J−1
This is because I2+Cl2⇌2I−Cl
2 moles of ICl are formed