Question

Bond energies can be obtained by using the following relation:

$\Delta H\left(reaction\right)=\sum$ Bond energy of bonds, broken in the reactants $-\sum$ Bond energy of bonds, formed in the products.

Bond energy depends on three factors:

a. greater is the bond length, lesser is the bond energy
b. bond energy increases with the bond multiplicity
c. bond energy increases with the electronegativity difference between the bonding atoms. Which among the following sequences is correct about the bond energy of $C-C$, $C=C$, and $C\equiv C$ bonds?

• A. $C=C>C\equiv C>C-C$
• B. $C\equiv C<C=C<C-C$
• C. $C\equiv C>C=C>C-C$
• D. $C\equiv C>C-C>C=C$

Answer 1

The correct option is C $C\equiv C>C=C>C-C$

bond energy of $C-C=347KJ/mole$
$C=C=620KJ/mole$
$C\equiv C=812KJ/mole$
so order is:
$C\equiv C>C=C>C-C$