Physical Properties - Alkenes
(i) Alkenes are odourless and colourless.
(ii) Alkenes are soluble in organic solvents and insoluble in water.
(iii) Physical state of Alkenes are:
C1 - C4 → gas
C4 - C16 → liquid
> C17 → solid wax
(iv) B.P. and M.P. decreases along with increasing branches in alkene.
(v) The melting points of cis isomers are lower than trans isomers as cis isomer is less symmetrical as compared to trans. So trans bundles much more hardly in the crystal lattice and therefore has a higher melting point.
(vi) The boiling points of cis isomers are bigger as compared to trans isomers as cis-alkenes has greater polarity (Dipole moment) than trans one.
(vii) These are lighter as compared to water.
(viii) Dipole moment: Alkenes are weakly polar. The, p-electron's of the double bond. Might be just simply polarized, Hence, their dipole moments are greater than those of alkanes.