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What is the dominant intermolecular force or bond that must be overcome in converting liquid $CH_3OH$ to a gas?
A
London dispersion force
B
Hydrogen bonding
C
Dipole-dipole interaction
D
Covalent bonds
Detailed Solution
Vaporisation separates the molecules from one another; the covalent bonds within each molecule are not broken.
In methanol, hydrogen is bonded to the highly electronegative oxygen atom, so the molecules are associated through intermolecular hydrogen bonds (O–H···O).
Hydrogen bonding is much stronger than the ordinary dipole–dipole and London dispersion forces that are also present.
This is why methanol has a much higher boiling point than compounds of similar molar mass that cannot form hydrogen bonds.
Hence the dominant force to be overcome is hydrogen bonding.
In methanol, hydrogen is bonded to the highly electronegative oxygen atom, so the molecules are associated through intermolecular hydrogen bonds (O–H···O).
Hydrogen bonding is much stronger than the ordinary dipole–dipole and London dispersion forces that are also present.
This is why methanol has a much higher boiling point than compounds of similar molar mass that cannot form hydrogen bonds.
Hence the dominant force to be overcome is hydrogen bonding.