Is the un saturation of benzene the same as that of alkenes and alkynes..? explain briefly.

Question

Is the un saturation of benzene the same as that of alkenes and alkynes..? explain briefly.

Answer 1

No it isn't.

The second bond in a double bond and the second and third bonds in a triple bond are called pi bonds and are much lower in energy than sigma bonds. The pi bonds are quite weak compared to sigma bonds and are quite reactive.

The pi electrons in the benzene ring are very unreactive. This is because In benzene, all the pi electrons in the benzene ring are conjugated. The pi electrons are de-localised around all the carbons in the ring. This feature is very stabilising. It takes a lot of energy to disturb this pi cloud and thus benzene pi bonds do not have a tendancy to react.

http://en.wikipedia.org/wiki/Aromaticity

Answer 2

Unsaturation of benzene is like that of alkene since alkene possesses double bond similarly in benzene there are three double bonds. Alkynes posses 2 pi bond and 1 sigma bond while alkene and benzene posses 1 pi and 1 sigma bond so benzene and alkene are less unsaturated than alkyne.