Is HF Polar or Nonpolar?

Answer: HF is a polar molecule due to the large electronegativity difference between hydrogen (2.20) and fluorine (3.98). This results in a partial negative charge on the latter and a partial positive charge on the former. This molecule has one of the strongest known permanent dipoles and is capable of hydrogen bonding. 

Due to HF having the greatest electronegativity difference between its two atomic components, the hydrogen bonds it forms have the greatest strength. Therefore, HF has a melting point of -84˚C and a boiling point of 20˚C. However, as you may notice, HF does not have a boiling point as high as H2O (where the melting point and boiling point are 0˚C and 100˚C, respectively). This is because HF is only capable of forming one hydrogen bond per molecule whereas H2O can form two hydrogen bonds per molecule (two hydrogens and two lone pairs). Although the hydrogen bonds formed by H2O (water) are individually weaker, together they form intermolecular forces stronger than those found in HF. However, it is the principle source of fluorine an extremely electronegative element. The molecule is also a very dangerous gas, forming hydrofluoric acid when it has contact with water. In fact, the gas can rapidly destroy critical parts of the human eye and thereby cause blindness.

HF Ball and Stick Model
HF Ball and Stick Model. Created with MolView.
How is HF utilized in the real world?

As has been alluded to earlier, HF is a source of fluorine both in its natural form and as it appears in more complex molecules such as fluorocarbons. HF participates in other reactions with various species in order to form these more complex molecules. In certain industries HF can be utilized as a "superacid" or a catalyst for specific reactions to produce certain kinds of pharmaceuticals or polymers. HF is similarly to H2O an excellent solvent of many types of polar molecules. However it is not utilized in practice due to the great danger posed by the molecule to human health if not handled properly. 

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