Arrange the following compounds in increasing order of carbon-carbon bond strength and explain the order.
`CH_(2)=CH_(2),CH_(3)-CH_(3),CH-=CH`

Explanation

Increasing order of C-C bond sterngth is given by:
`C-C lt C=C lt C=C`
i.e., `CH_(3)-CH_(3) lt CH_(2) =CH_(2) lt CH-=CH`
Greater the bond multiplicity, greater is the bond dissociation enthalpy. In `CH_(3)-CH_(3)`, there is only one `sigma`-bond between the C-atoms whereas, `CH_(2)=CH_(2) and CH-=CH` contains one and two `pi`-bonds respectively, in addition to the `sigma`-bond. so the energy required to break the carbon-carbon bonds increases in the order `C-C lt C=C lt C-=C`.