CH3Cl, also known as chloromethane, is a polar molecule. The polarity of CH3Cl arises due to the difference in electronegativity between the carbon (C), hydrogen (H), and chlorine (Cl) atoms.
In CH3Cl, the carbon atom is bonded to three hydrogen atoms and one chlorine atom. Chlorine is more electronegative than carbon, which means it attracts the shared electrons in the C-Cl bond more strongly. This creates a dipole moment, where the chlorine end of the molecule has a partial negative charge (δ-) and the carbon end has a partial positive charge (δ+).
Additionally, the three C-H bonds are relatively nonpolar because the electronegativity difference between carbon and hydrogen is small. However, the overall shape of the molecule (tetrahedral) and the presence of the polar C-Cl bond result in a net dipole moment, making CH3Cl a polar molecule.
In summary, CH3Cl is polar due to the significant electronegativity difference between carbon and chlorine, which creates a dipole moment in the molecule.