Both polarity and molar mass affect the melting points of a compounds. However, polarity is more prioritized for compounds of similar molar mass. The order of increasing melting point follows: non-polar < polar < ionic.
Ionic compounds have the strongest forces holding them which is why it requires higher temperature to overcome those forces. Next, polar substances have weaker electrostatic forces than ionic compounds, but have stronger forces than non-polar compounds due to the presence of dipole-dipole interaction. The force present in non-polar compounds is Van Der Waals forces.
