The gas-phase HCl molecule has a measured bond dipole moment of 1.08 D and a bond length of 127 pm.
Useful constants: 1 D = 3.34×10−30C⋅m; elementary charge e=1.60×10−19C.
(a) Determine the maximum possible dipole moment, in debye, for complete transfer of one electron across the 127 pm bond length.
(b) Calculate the percent ionic character of the H–Cl bond.
(c) Classify the H–Cl bond as predominantly covalent, predominantly ionic, or intermediate in character, and justify your classification based on the value obtained in part (b).
(d) Experimental measurements show that the H–Cl bond dissociation energy (431 kJ mol−1) is significantly less than that of the H–F bond (567 kJ mol−1). Discuss how differences in ionic character help account for this observation.