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Why does cis-alkene have a higher boiling point, while trans-alkene has a higher melting point?
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+ Chemistry
+ Hydrocarbons
+ Organic chemistry
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Linda C. Ragin
Why does cis-alkene have a higher boiling point, while trans-alkene has a higher melting point?
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.
The boiling point is decided by two parameters : Molecular mass and polarity. In cis and trans compounds, most of them have same molecular mass but polarity of cis compound is more than trans compound. Because in trans, the same bonds are exactly opposite each other thus making dipole moment equals to zero but cis gives resultant dipole moment. Thus boiling point of cis is more than trans.
For deciding melting point, the first and foremost parameter is symmetrical order and crystallinity. In trans compound, symmetry is more whereas in cis, symmetry is less. Thus trans has higher melting point than cis.
The boiling point is decided by two parameters : Molecular mass and polarity. In cis and trans compounds, most of them have same molecular mass but polarity of cis compound is more than trans compound. Because in trans, the same bonds are exactly opposite each other thus making dipole moment equals to zero but cis gives resultant dipole moment. Thus boiling point of cis is more than trans.
For deciding melting point, the first and foremost parameter is symmetrical order and crystallinity. In trans compound, symmetry is more whereas in cis, symmetry is less. Thus trans has higher melting point than cis.
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.
Thank you.
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.
Thank you.
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The boiling point is decided by two parameters : Molecular mass and polarity. In cis and trans compounds, most of them have same molecular mass but polarity of cis compound is more than trans compound. Because in trans, the same bonds are exactly opposite each other thus making dipole moment equals to zero but cis gives resultant dipole moment. Thus boiling point of cis is more than trans.
For deciding melting point, the first and foremost parameter is symmetrical order and crystallinity. In trans compound, symmetry is more whereas in cis, symmetry is less. Thus trans has higher melting point than cis.
Thanks for A2A !
The boiling point is decided by two parameters : Molecular mass and polarity. In cis and trans compounds, most of them have same molecular mass but polarity of cis compound is more than trans compound. Because in trans, the same bonds are exactly opposite each other thus making dipole moment equals to zero but cis gives resultant dipole moment. Thus boiling point of cis is more than trans.
For deciding melting point, the first and foremost parameter is symmetrical order and crystallinity. In trans compound, symmetry is more whereas in cis, symmetry is less. Thus trans has higher melting point than cis.
Thanks for A2A !
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