The bond dissociation of `C=C` in ethene is

Options

A. `63 kcal mol^(-1)`
B. `146 kcal mol^(-1)`
C. `88 kcal mol^(-1)`
D. `95 kcal mol^(-1)`

Answer

B

Explanation

The `C=C` bond of ethene has the greater bond dissociation energy `(146 kcal mol^(-))` compared to the `C-C` bond of ethane `(88 kcal mol^(-1))` because with `C=C`, two bonds are broken and with `CoC`, only one. In spite of the greater bond dissociation energy of the double bond, alkenes are more reactive than alkanes beacuse in most reactions, only `pi` bond is broken. Its bond dissociation energy of `51 kcal mol^(-1)` is less than bond dissociation energy of `C-C sigma` bond of ethane.