Question

Bond energy is maximum in
A. $O - O$
B.$C \equiv C$
C.$C \equiv N$
D.$N \equiv N$

Answer 1

Hint: The strength of a chemical bond is measured in bond energy. It is the amount of energy necessary to break all covalent bonds of a particular kind in a single mole of a chemical molecule (which is in its gaseous state).

Complete answer:
Bond energy of $O - O$ is $142kJ/mol$.
Bond energy of $C \equiv C$is $835kJ/mol$.
Bond energy of $C \equiv N$ is $887kJ/mol$.
Bond energy of $N \equiv N$ is $942kJ/mol$ .
From the above values of bond energy, we can say that $N \equiv N$ has maximum bond energy among the given compounds.
The maximum bond energy is of $N \equiv N$ because the molecule is formed by three covalent bonds and is smaller in size than $C \equiv C$. $O - O$ is formed by a single bond.
Hence, the correct option is D.$N \equiv N$.

Additional information: Bond energy is directly proportional to the bond length. Bond energy is directly proportional to bond order. It is inversely proportional to the atomic radii of the atoms participating in the bond.

Note:
Bond enthalpy, also known as bond-dissociation enthalpy, average bond energy, or bond strength, is the amount of energy contained in a bond between atoms in a molecule. In fact, it is the energy that must be given to the homolytic or symmetrical cleavage of a bond in the gas phase.It's important to distinguish between bond energy and bond dissociation energy. The former is the average of the bond dissociation enthalpies of all bonds (of a certain type) in a molecule, whereas the latter is the change in enthalpy associated with the homolytic cleavage of a bond.