The carbon tetrachloride molecule (CCl4) is a nonpolar molecule with polar bonds.
The correct answer and explanation is:
The statement is true. Carbon tetrachloride (CCl4) is a nonpolar molecule, even though it contains polar bonds.
Here’s why:
- Polar Bonds: In CCl4, each carbon atom is covalently bonded to four chlorine atoms. Chlorine is more electronegative than carbon, meaning that the shared electrons in each C-Cl bond are pulled closer to the chlorine atom, creating a dipole moment. This makes each individual C-Cl bond polar, with the chlorine atoms having a partial negative charge and the carbon atom having a partial positive charge.
- Symmetry of the Molecule: Despite the polar bonds, CCl4 is a tetrahedral molecule with symmetry. The carbon atom is at the center of the molecule, and the four chlorine atoms are arranged symmetrically around it. This symmetry ensures that the dipoles from the individual C-Cl bonds cancel each other out. The bond dipoles point in opposite directions, and because of the molecule’s symmetrical geometry, these dipoles sum to zero. This results in the overall molecule being nonpolar.
- Molecular Dipole Moment: The overall dipole moment of CCl4 is zero, even though the individual C-Cl bonds are polar. This is because the vector sum of the dipoles from the bonds cancels out due to the molecule’s symmetry. Thus, the molecule does not have a net dipole moment and is classified as nonpolar.
In summary, while CCl4 contains polar covalent bonds, its symmetrical tetrahedral structure causes the individual bond dipoles to cancel, making the molecule as a whole nonpolar. This demonstrates that the polarity of individual bonds does not necessarily determine the overall polarity of the molecule.