Chapter 9, Problem 9.93PAE

9.99 The chemical reaction ${\text{BBr}}_{\text{3}}\left(\text{g}\right)+{\text{BCl}}_{\text{3}}\left(\text{g}\right)\to {\text{BBr}}_{\text{2}}\text{Cl}\left(\text{g}\right)+{\text{BCl}}_{\text{2}}\text{Br}\left(\text{g}\right)$ , has an enthalpy change very close to zero. Using Lewis structures of the molecules, all of which have a central boron atom, provide a molecular-level description of why $\Delta \text{H}°$ for this reaction might be very small.