Chapter 6, Problem 103RQ

The value of $\Delta H_{\text{f}}^{\text{°}}$ for HBr(g) was first evaluated using the following standard enthalpy values obtained experimentally. Use these data to calculate the value of $\Delta H_{\text{f}}^{\text{°}}$ for HBr(g).

$\begin{array}{l}{\text{Cl}}_{\text{2}}\left(g\right)+2\text{KBr}\left(aq\right)\to {\text{Br}}_{\text{2}}\left(aq\right)+2\text{KCl}\left(aq\right)\Delta H°=-96.2\text{ kJ}\\ {\text{H}}_{\text{2}}\left(g\right)+{\text{Cl}}_{\text{2}}\left(g\right)\to 2\text{HCl}\left(g\right)\Delta H°=-184\text{ kJ}\\ \text{HCl}\left(aq\right)+\text{KOH}\left(aq\right)\to \text{KCl}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\Delta H°=-57.3\text{ kJ}\\ \text{HBr}\left(aq\right)+\text{KOH}\left(aq\right)\to \text{KBr}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\Delta H°=-57.3\text{ kJ}\\ \text{HCl}\left(g\right)\stackrel{\text{dissolving in water}}{\to }\text{HCl}\left(aq\right)\Delta H°=-77.0\text{ kJ}\\ {\text{Br}}_{\text{2}}\left(g\right)\stackrel{\text{dissolving in water}}{\to }{\text{Br}}_{\text{2}}\left(aq\right)\Delta H°=-4.2\text{ kJ}\\ \text{HBr}\left(g\right)\stackrel{\text{dissolving in water}}{\to }\text{HBr}\left(aq\right)\Delta H°=-79.9\text{ kJ}\end{array}$