CHBr3, also known as bromoform, is a polar molecule. This polarity arises from its molecular geometry and the difference in electronegativity between its constituent atoms.
The central carbon atom in CHBr3 is bonded to three bromine atoms and one hydrogen atom. Bromine is much more electronegative than hydrogen, which creates a significant difference in the distribution of electron density across the molecule. As a result, the C-Br bonds are polarized, with a partial negative charge (δ-) on the bromine atoms and a partial positive charge (δ+) on the carbon atom.
Furthermore, the molecular shape of CHBr3 is tetrahedral. The three bromine atoms create a region of negative charge due to their electronegativity, while the hydrogen atom provides a region of positive charge. Because of this arrangement, the dipoles of the C-Br bonds do not cancel out and lead to an overall polar molecule.
In summary, the combination of unequal bond polarities and the shape of the molecule confirms that CHBr3 is polar.