Final answer:
CHCl3 (chloroform) is a polar molecule due to the asymmetry created by the three polar C-Cl bonds and one slightly polar C-H bond. This asymmetry leads to a net dipole moment, making the molecule polar despite its tetrahedral geometry.
Step-by-step explanation:
CHCl3, commonly known as chloroform, is a tetrahedral molecule that exhibits polarity. The molecule consists of a central carbon atom surrounded by three chlorine atoms and one hydrogen atom. The relative electronegativities of the bonded atoms contribute to this polarity, with hydrogen being less electronegative than carbon, which in turn is less electronegative than chlorine. Consequently, each C-Cl bond is polar, with the bond moments pointing towards chlorine, and the C-H bond being slightly polar. Due to the asymmetric distribution of these polar bonds, the overall dipole moments do not cancel out, yielding a molecule with a considerable dipole moment and polar character.
In the context of tetrahedral geometry, a molecule such as CH4 would be nonpolar because all of its peripheral atoms are identical, leading to bond moments that cancel out each other. However, replacing one of the peripheral H atoms in CH4 with a more electronegative atom, as seen in CHCl3, results in a polar molecule because the symmetry is disrupted, and the bonds' dipole moments no longer cancel out completely.