You are given samples of ethane, ethene and ethyne in three different containers. How will you distinguish them?
Benzene ring has three double bonds in it but is still quite stable. Explain.
Or
Why is benzene extra-ordinary stable though it contains three double bonds?
Each carbon atom of benzene is sp2 hybridised. The unhybridised p-orbital of each carbon atom overlaps to a small but equal extent with the unhybridised p-orbitals of both the adjacent carbon atoms. This leads to the formation of molecular orbital embracing all the six carbon atoms. Due to the delocalisation of –electron clouds above and below the plane of the benzene ring, all the carbon-carbon bonds acquire slight double bond character. Thus carbon-carbon bond length in benzene lies in between C–C and C=C bond length.
Standard C–C bond length = 154 pm
Standard C=C bond length = 134 pm
But C–C bond length in benzene = 139 pm.