As the chain length of a hydrocarbon is increased the heat of vapourization
increases because
Select one:
O a. the molecules have greater weight
O b. there are more hydrogens available for hydrogen bonding
c. the number of dipole-dipole interactions increases
O d. the strength of the London forces increases with molecular size
the carbon-carbon bonds become more polar
Answer is d, strength of London forces increases with molecular size.
Explanation:
Dispersion forces are the forces preesnt between all intermingling atoms, molecules and particles. Dispersion forces are the weakest intermolecular force, but they build up with the addition of more atoms, molecules or particles. Heat of vapourisation or boiling point is dependant on the energy required to break the bonds within the molecule/hydrocarbon in question. The build up of dispersion forces create greater intermolecular forces, which make the boiling of a substance more difficult. Hence increased hydrocarbon chain length, and the related increased eat of vapourisation is due to how the strength of the London/Dispersion forces increases with molecular size
