Hex-2-ene is represented as
\( CH_3- CH =CH - CH_2 -CH_2 -CH_3 .\) .
Geometrical isomers of hex-2-ene are:
The dipole moment of cis-compound is a sum of the dipole moments of \( C -CH_3\; and\;C - CH_2 CH_2 CH_3\) bonds acting in the same direction. The dipole
moment of a trans-compound is the resultant of the dipole moments of the same bonds acting in opposite directions. Thus, cis-isomer is more polar than trans-isomer. The higher the polarity, the greater is the intermolecular dipole-dipole interaction and the higher will be the boiling point. Therefore, cis-isomer will have a higher boiling point than trans-isomer.