Distincton of Alkanes and Alkenes. On the left:Cyclohexane does not react with water bromide On the right:Cyclohexene does.
Alkenes are weakly polar just like alkanes but are slightly more reactive than alkanes due to the presence of double bonds. The π electrons which make up the double bonds can easily be removed or added as they are weakly held. Hence the dipole moments exhibited by alkenes are more than alkanes.
Aromatic compounds are often drawn as cyclic alkenes, but their structure and properties are different and they are not considered to be alkenes.[2]
The double bond in the middle makes them more reactive because the molecule is not saturated. An alkene's unsaturation means that it will take the color out of bromine. The names of alkenes always end with -ene.
Alkenes areweakly polar just like alkanes but are slightly more reactive than alkanes due to the presence of double bonds. The π electrons which make up the double bonds can easily be removed or added as they are weakly held. Hence thedipole moments exhibited by alkenes are more than alkanes.
The physical properties of alkenes are comparable with those ofalkanes. The main differences between the two are that theacidity levels of alkenes are much higher than the ones in alkanes. Thephysical state depends onmolecular mass (gases from ethene to butene - liquids from pentene onwards). The simplest alkenes,ethene,propene andbutene are gases. Linear alkenes of approximately five to sixteen carbons are liquids, and higher alkenes are waxy solids.
