The enthalpy changes of formation, $\Delta H_f^\circ$, for both $\text{PCl}_3$ and $\text{PCl}_5$ are exothermic. $\text{PCl}_3$ reacts with chlorine. $\text{PCl}_3(l) + \text{Cl}_2(g) \rightarrow \text{PCl}_5(s) \quad \Delta H^\circ_{reaction} = -124\,\text{kJ mol}^{-1}$. Which two statements are correct?
- A$\Delta H^\circ_{reaction}$ is less negative than $\Delta H_f^\circ(\text{PCl}_5)$. The $\text{Cl}_2$ bond energy is needed in calculating $\Delta H^\circ_{reaction}$ from enthalpies of formation.
- B$\Delta H^\circ_{reaction}$ is more negative than $\Delta H_f^\circ(\text{PCl}_5)$. The $\text{Cl}_2$ bond energy is needed in calculating $\Delta H^\circ_{reaction}$ from enthalpies of formation.
- C$\Delta H^\circ_{reaction}$ is less negative than $\Delta H_f^\circ(\text{PCl}_5)$. The $\text{Cl}_2$ bond energy is not needed in calculating $\Delta H^\circ_{reaction}$ from enthalpies of formation.
- D$\Delta H^\circ_{reaction}$ is more negative than $\Delta H_f^\circ(\text{PCl}_5)$. The $\text{Cl}_2$ bond energy is not needed in calculating $\Delta H^\circ_{reaction}$ from enthalpies of formation.