Question

The bond energy of a C–C single bond averages 347 kJ mol⁻¹; that of a C≡C triple bond averages 839 kJ mol⁻¹. Explain why the triple bond is not three times as strong as a single bond.

a) Due to resonance
b) Due to increased electron repulsion
c) Due to the shorter bond length
d) Due to decreased electron density between the nuclei

Answer 1

The triple bond is not three times as strong as a single bond due to resonance, shorter bond length, and increased electron repulsion. Correct option is b.

Step-by-step explanation:

The bond energy of a C-C single bond is 347 kJ/mol, while the bond energy of a C=C triple bond is 839 kJ/mol. The triple bond is not three times as strong as a single bond because of several factors. One reason is due to resonance, which allows for delocalization of electrons, increasing the stability of the bond. Another reason is the shorter bond length in a triple bond, which leads to greater electron density between the nuclei, resulting in a stronger bond. Lastly, the increased electron repulsion between the multiple bonds also contributes to the higher bond energy of a triple bond.