Question

$ C—H $ bond energy is about $ 101\, kcal/mol $ for methane, ethane and other alkanes but is only $ 77\, kcal/mol $ for $ C—H $ bond of $ CH_3 $ in toluene. This is because :

• A. of inductive effect due to $ —CH_3 $ in toluene
• B. of the presence of benzene ring in toluene
• C. of resonance among the structures of benzyl radical in toluene
• D. aromaticity of toluene

Answer 1

Answer: (C)

$\because \,C - H$ bond in toluene has partial double bond character due to resonance

$\therefore \, C - H$ bond in toluene has less energy as compared to others.