Which type of alkene has high boiling point of cis and alkene and why?
Which type of alkene has high boiling point of cis and alkene and why?
Polarity is the key in determining relative boiling point as it causes increased inter-molecular forces, thereby raising the boiling point. The difference in the boiling point between cis and trans isomers arises due to presence of polar bonds in cis isomer.
In cis isomers there are dipole-dipole forces which add to the London dispersion forces (A weak inter-molecular force arising from polarization) and raise the boiling point, while in the case of trans isomers the net dipole moment is zero that’s why trans isomers have lower boiling point than cis isomers.
In the same manner, Symmetry is key in determining relative melting point as it allows for better packing in the solid state, even if it does not alter the polarity of the molecule.
The trans isomers have symmetrical structure than the cis isomers that is why trans isomers have high melting point than the cis isomers.
Thus, trans alkenes, which are less polar and more symmetrical, have lower boiling points and higher melting points, and cis alkenes, which are generally more polar and less symmetrical, have higher boiling points and lower melting points.
Polarity is the key in determining relative boiling point as it causes increased inter-molecular forces, thereby raising the boiling point. The difference in the boiling point between cis and trans isomers arises due to presence of polar bonds in cis isomer.
In cis isomers there are dipole-dipole forces which add to the London dispersion forces (A weak inter-molecular force arising from polarization) and raise the boiling point, while in the case of trans isomers the net dipole moment is zero that’s why trans isomers have lower boiling point than cis isomers.
In the same manner, Symmetry is key in determining relative melting point as it allows for better packing in the solid state, even if it does not alter the polarity of the molecule.
The trans isomers have symmetrical structure than the cis isomers that is why trans isomers have high melting point than the cis isomers.
Thus, trans alkenes, which are less polar and more symmetrical, have lower boiling points and higher melting points, and cis alkenes, which are generally more polar and less symmetrical, have higher boiling points and lower melting points.
