Question

1. Which of the following transition(s) is/are necessary to construct a Born Haber Cycle for the formation of NaCl solid?

Multiple answers: You can select more than one option

A) Na(s) → Na(l)

B) Na(s) → Na(g)

C) Na(g) → Na^+​+​​(g) + e^-​−​​

D) Cl_2​2​​(g) → 2Cl(g)

E) Na(s) + ½ Cl_2​2​​(g) →NaCl(s)

2. Which of these transitions are exothermic processes? Multiple answers are accepted.

A) Na(g) → Na(l)

B) Na(s) → Na(g)

C) Na(g) → Na^+​+​​(g) + e^-​−​​

D) Cl_2​2​​(g) → 2Cl(g)

E) Cl(g) + e^-​−​​→ Cl^-​−​​(g)

Answer 1

1)

B,C,D and E are Answers.

In Born Haber cycle the reactions are as follows.

2)

B : It is an endothermic reaction. Because for this sublimation transition energy has to be supplied to the system as  ΔH_sub = +108 KJ.(positive sign)

C: It is an endothermic reaction. Because Ionization energy is positive for the transition so energy has to be supplied to the system as IE= +496KJ.(postive sign)

D : It is an endothermic reaction. Because for this dissociation transition energy has to be supplied to the system as  ΔH_dis = +122 KJ.(postive sign)

E : It is an exothermic reaction. As the heat evolves from the system as this transition occurs. ( as the sign of EA= -349KJ is negative.)