Question

which of the following compounds possesses the C-H bond with the lowest bond dissociation energy?
1/toulene
2/benzene
3/n pentane
4/2,2 dimethylpropane​

Answer 1

a) Toluene

(b) Benzene

(c) n-Pentane

(d) 2,2-Dimethylpropane

Correct Answer:

Toluene

Explanation:

Structure of Toluene:



Toluene (C₆H₅CH₃) = 85 kcal/mol

Benzene (C₆H₆) = 110 kcal/mol

n-Pentane (CH₃CH₂CH₂CH₃ ) = 98 kcal/mol

2, 2-Dimathylpropane= 92 kcal/mol

Toluene has the lowest C – H bond dissociation energy compare to other three.

Toluene is a Tertiary free radical. Bond Dissociation Energy of C-H bonds decreases as we go from methyl to primary to secondary to tertiary. They are easier to break since homolytic bond cleavage results in a more stable radical.

Answer 2

Answer:Toluene

Explanation: