Is a molecule of hydrogen chloride (HCl) polar or nonpolar?

A molecule of hydrogen chloride (HCl) is polar.

To determine whether a molecule is polar or nonpolar, you can use the concept of electronegativity. Electronegativity is a measure of an atom's ability to attract electrons within a covalent bond. In the case of HCl, hydrogen (H) and chlorine (Cl) have significantly different electronegativities. Chlorine is much more electronegative than hydrogen.

In an HCl molecule, the chlorine atom attracts the shared electrons in the H-Cl bond more strongly than the hydrogen atom does. As a result, the electrons in the bond are closer to the chlorine atom, creating a partial negative charge (δ-) on the chlorine atom and a partial positive charge (δ+) on the hydrogen atom.

This charge separation results in an uneven distribution of charge within the molecule, making it polar. The polarity of HCl gives rise to its unique properties, such as its ability to dissolve in polar solvents and its strong dipole-dipole interactions.