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Chemical Bonding And Molecular Structure

Question
CBSEENCH11005792

Show that N2 molecule has a greater bond dissociation energy than N-2 where O2 has lower bond dissociation energy than O+2.

Solution

The bond dissociation energy is directly proportional to bond order such that,
greater the bond order,  greater is the bond dissociation energy.
   Bond space order space space equals space 1 half left square bracket straight N subscript straight b space minus space straight N subscript straight a right square bracket
therefore space space space space Bond space order space of space straight N subscript 2 space equals space 1 half left square bracket 8 minus 2 right square bracket space equals 1 half cross times 6 space equals space 3
Bond space order space of space straight N subscript 2 superscript minus space equals space 1 half left square bracket 8 minus 3 right square bracket space equals space 5 over 2 space equals space 2.5
Bond space order space of space straight O subscript 2 space equals space left square bracket 8 minus 4 right square bracket space equals space 4 over 2 space equals space 2
Bond space order space of space straight O subscript 2 superscript plus space equals space 1 half left square bracket 8 minus 3 right square bracket space equals space 5 over 2 space equals space 2.5

∴   N2 has greater bond dissociation energy than  N-2. O2 has a lower bond dissociation energy than O+2.