Alkenes and Alkynes
Physical Properties of Alkenes :
(a)All are colourless & have no characteristic odour. Ethene has pleasant smell.
(b)Lower members (C2 to C4) are gases, middle one (C3 to C17) are liquids, higher are solids.
(c)The boiling points, melting points, and specific gravities show a regular increase with increase in molecular weight, however less volatile than corresponding alkanes.
(d)A cis isomer has high boiling and melting point than trans isomer because of more polar nature.
(e)Like alkanes, these too are soluble in non polar solvents.
(f)Alkenes are weak polar. The polarity of cis isomer is more than trans which are either non polar or less polar. (e.g. trans butene-2 is non polar; trans pentene-2 is weak polar).