Question

Explain why the bond dissociation energy for bond (a) is lower than the bond dissociation energy for bond (b).

Short answer

Answer

Bond b has higher bond dissociation energy than bond a as it is adjacent to a double bond.

Step-by-step solution

Step-by-Step SolutionStep 1: Bond dissociation energy

The energy required to break a chemical bond is termed bond dissociation energy.

As the number of bonds between two atoms increases, the bond dissociation energy also increases.

Skeletal structures of the given compounds

The skeletal structures of the given compounds are as follows:Skeletal structure of a

Skeletal structure of b

Bond dissociation energy of compounds a and b

Bond b has higher dissociation energy than a as it is adjacent to a double bond, or in other words, b involves bond formation between ${\mathrm{sp}}^2$and sp hybridized carbon atoms.

In the case of bond a, both the carbon atoms involved in bonding are ${\mathrm{sp}}^3$hybridized.

As the percent s character of the atoms involved in bonding increases, the bond strength increases, and the bond dissociation energy also increases.