Answer:
Because dipole - dipole force is stronger than london dispersion force
Step-by-step explanation:
Intermolecular forces determines a wide range of physical properties of matter of which melting point is one of them.
Both london dispersion forces and dipole- dipole forces are vanderwaals force.
But diople - dipole forces exists between polar molecules which are molecules with permanent dipoles.
In london dispersion forces the dipole is temporary