Question

Caesium chlorides is formed according to the following equation Cs(s) + 0.5 Cl2(g) $\rightarrow$CsCl(s). The enthalpy of sublimation of Cs, enthalpy of dissociation of chlorine, ionization energy of Cs and electron affinity of chlorine are 81.2, 243.0, 375.7 and –348.3 kJ mol–1. The energy change involved in the formation of CsCl is –388.6 kJ mol–1. Calculate the lattice energy of CsCl.

• A. 618.7 kJ mol–1
• B. 1237.4 kJ mol–1
• C. –1237.4 kJ mol–1
• D. –618.7 kJ mol–1

Answer 1

Answer: (D)

–618.7 kJ mol–1

Answer 2

Apply Born Haber’s cycle