Why do molecules with dipole-dipole force have higher melting and boiling points than molecules that only exhibit London Dispersion force?

Because dipole - dipole force is stronger than london dispersion force

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

warm front forms when a moist, warm air mass slides up and over a cold air mass. as the warm air mass rises, it condenses into a broad area of clouds. a warm front brings gentle rain or light snow, followed by warmer, milder weather.

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