Given that, bond energies of H−H and Cl−Cl ar 430kJ/mol and 240kJ/mol respectively. ΔHf for HCl is −90kJ/mol. Bond enthalpy of HCl is:
Given that bond energies of H–H and Cl−Cl are 430 kJ mol−1 and 240 kJ mol−1 respectively and ΔfH for HCl is -90 kJ mol−1. The bond enthalpy of HCl is: