Question

Construct a Born–Haber cycle for the formation of the hypothetical compound NaCl₂, where the sodium ion has a 2+ charge (the second ionization energy for sodium is given in Table 7.2). (a) How large would the lattice energy need to be for the formation of NaCl₂ to be exothermic? (b) If we were to estimate the lattice energy of NaCl₂ to be roughly equal to that of MgCl₂ (2326 kJ/mol from Table 8.2), what value would you obtain for the standard enthalpy of formation, ∆Hf°, of NaCl₂?