Question

When 1 mole of crystalline NaCl is obtained from sodium and chlorine gas, 410 kJ of heat is released. The heat of sublimation of sodium metal is 108 kJ mol^–l and Cl-Cl bond enthalpy is 242 kJ mol^–l . If the ionization energy of Na is 493.0 kJ mol^–l and the electron affinity of chlorine is 368 kJ mol^–l , the lattice energy of NaCl is

a. 764 kJ mol^-l

b. -764 kJ mol^-l 

c. 885 kJ mol^-l

d. -885 kJ mol^-l

Answer 1

Correct option is b. -764 kJ mol^-1