Chemistry · THERMODYNAMICS

Consider the following statements regarding the Born-Haber cycle for \( \text{NaCl(s)} \): (A) Sublimation of metallic sodium is an endothermic step. (B) Ionization of gaseous sodium atoms to \( \text{Na}^+(\text{g}) \) is an exothermic step. (C) Dissociation of \( \text{Cl}_2(\text{g}) \) molecules into \( \text{Cl}(\text{g}) \) atoms is an endothermic step. (D) Electron gain by \( \text{Cl}(\text{g}) \) to form \( \text{Cl}^-(\text{g}) \) is an exothermic step. Which of the above statements are correct?

1. A
   (A) and (B) only
2. B
   (A), (C) and (D) only
3. C
   (B), (C) and (D) only
4. D
   All (A), (B), (C) and (D)