* Electronegativity Difference: Bromine (Br) is more electronegative than hydrogen (H). This means bromine attracts the shared electrons in the H-Br bond more strongly.

* Uneven Electron Distribution: The shared electrons spend more time closer to the bromine atom, creating a partial negative charge (δ-) on the bromine and a partial positive charge (δ+) on the hydrogen.

* Dipole Moment: This uneven distribution of charge creates a dipole moment, where one end of the molecule has a positive charge and the other end has a negative charge.

Therefore, HBr is a polar molecule.