Though the dipole moment of HF and ethyl fluoride is same yet the boiling point of ethyl fluoride isapprx -37⁰C and that of HF is 19⁰C approx. Why?

Since the dipole moment of Ethyl Fluoride and Hydrogen Fluoride is same, its not of concern here, but rather only van der waals forces which depend mainly on the size of the molecule

The strength is based on intermolecular interactions.

Ethyl Fluoride is nonpolar and have very weak interactions between the molecules resulting in a low boiling point.

Hydrogen Fluoride forms hydrogen bonding which is harder for it to break apart because the bond are stronger. Resulting that the HF boiling point is much higher.

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