In Section 5.6, we learned that triple bonds are stronger and shorter than single bonds. For example, a C- Csingle bond has an average bond energy of 347 k. J/mole, while a C C triple bond has an average bond energy of 837 k. J/mole. Use valence bond theory to explain why a triple bond is not simply three times as strong as a single bond. A) The C C triple bond is an exception. According to valence bond theory, a triple bond is generally three times as strong as a single bond. B) Because according to valence bond theory, a triple bond is the sharing of four electron pairs.
C) Because according to valence bond theory, a triple bond is actually composed of two different kinds of bonds, one σ and two π

Because according to valence bond theory, a triple bond is actually composed of two different kinds of bonds, one σ and two π

Explanation:

The respective bond a energies of C-C single, double and triple bonds are; 347KJmol-1, 681 KJmol-1 and 837 KJmol-1 respectively.

It can be seen that the bond energy of a triple bond is really not thrice the bond energy of a C-C single bond. This is because, a triple bond is composed of two different kinds of bonds. A C-C sigma bond and two C-C pi bonds. The C-C sigma bonds are stronger than the C-C pi bonds because sigma bonds result from a greater degree of overlap between the atomic orbitals involved in the bond.

Hence, the C-C triple bond energy is not simply three times that of the C-C single bond energy since there are actually two different kinds of bonds present as explained above.

level 4 to level 2 : ))