The bond enthalpy in NO is 632 kJ · mol^–1 and that of each N—O bond in NO₂ is 469 kJ · mol^–1. Using Lewis structures and the data in Table 4E.3, explain

(a) The difference in bond enthalpies between the two molecules;

(b) The fact that the bond enthalpies of the two bonds in NO₂ are the same.

TABLE 4E.3 Mean Bond Enthalpies Bond C-H C-C C=C CC* C=C C-N C-F C-Cl C-Br AHB/(kJ.mol-) 412 348 612 518 837 360 743 305 484 338 276 Bond C-I N-H N-N N=N N-O N=O N-F N-Cl O-H 0-0 AHB/(kJ.mol-) 238 388 163 409 210. 630. 270. 200. 463 157