Question

For NaCl: ΔsubH(Na) = 108, ΔiH(Na) = 496, ½ΔdissH(Cl2) = 121, ΔegH(Cl) = −349 and ΔfH(NaCl) = −411 (all in kJ mol−1). The lattice enthalpy of NaCl is

Use the following data (in kJ mol⁻¹) for NaCl: ΔfH°(NaCl, s) = −411; enthalpy of sublimation of Na = 108; ionisation enthalpy of Na = 496; bond dissociation enthalpy of Cl2 = 242; electron gain enthalpy of Cl = −349. The lattice enthalpy of NaCl (energy needed to separate 1 mol of the solid into gaseous ions) is: