Question

Which one of, the following bonds has the highest average bond energy (kJ/mol)?

• A. S = O
• B. $C\equiv C$
• C. $C\equiv N$
• D. $N\equiv N$

Answer 1

The correct option is D. $N\equiv N$
We know that a single bond is weaker than a double bond similarly double bond is weaker than a triple bond. Hence $C\equiv N$ and $N\equiv N$ is the strongest bond (highest average bond energy).
Now, out of these two \ (C \equiv N\) is a polar bond $N\equiv N$ is a nonpolar bond and we know that the nonpolar bond will be stronger than the polar bond.
Here is the average bond energy of given bonds are,
B.E of S = O, $C\equiv C,C\equiv N$ and $N\equiv N$ are 525, 839, 891 and $941kJ/mo{l}^{-1}$ respectively.
Hence $N\equiv N$ has the highest average bond energy.