Question

Which of the following statements is true? Aromatic compounds release more energy per pi bond upon saturation than simple alkenes. Aromatic compounds release more energy on combustion than aliphatic compounds do. Aromatic compounds have shorter C-C bonds than CH2=CH2 Aromatic compounds do not react in radical halogenation as compared to aliphatic compounds

Answer 1

Option c that is aromatic compounds have shorter C-C bonds than CH₂=CH₂.

Since, in aromatic system conjugation takes place the c-c bond becomes shorter than isolate C-C bond.

Since they are involved in conjugation they have less energy than isolated system.

So, energy per pi bond is less in aromatic system due to conjugation.

When a system is less stable it releases more heat on combustion. Aromatic compounds being more stable due to conjugation release less energy.

Due to delocalization aromatic reacts faster than alliphatic compounds in radical halogenation