Chapter 3, Problem 23P

Use the data in Figure 3.11 and Table 3.2 to calculate the energy changes $\left(\Delta \text{E}\right)$ for the following pairs of reactions:

(a) $\text{K}\left(\text{g}\right)+\text{Cl}\left(\text{g}\right)\to {\text{K}}^{+}\left(\text{g}\right)+{\text{Cl}}^{-}\left(\text{g}\right)$

$\text{K}\left(\text{g}\right)+\text{Cl}\left(\text{g}\right)\to {\text{K}}^{-}\left(\text{g}\right)+{\text{Cl}}^{+}\left(\text{g}\right)$

(b) $\text{Na}\left(\text{g}\right)+\text{Cl}\left(\text{g}\right)\to {\text{Na}}^{+}\left(\text{g}\right)+{\text{Cl}}^{-}\left(\text{g}\right)$

$\text{Na}\left(\text{g}\right)+\text{Cl}\left(\text{g}\right)\to {\text{Na}}^{-}\left(\text{g}\right)+{\text{Cl}}^{+}\left(\text{g}\right)$

Explain why ${\text{K}}^{+}{\text{Cl}}^{-}$ and ${\text{Na}}^{+}{\text{Cl}}^{-}$ form in preference to ${\text{K}}^{-}{\text{Cl}}^{+}$ and ${\text{Na}}^{-}{\text{Cl}}^{+}$ .