The enthalpies of atomization of CH4(g) and C2H6(g) are respectively 400 kJ mol−1 and 670 kJ mol−1. The value of △HC−C would be
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: