Is CCl₄ polar or nonpolar?

No, $\ce{CCl4}$ (carbon tetrachloride) is nonpolar despite having polar $\ce{C-Cl}$ bonds. While each $\ce{C-Cl}$ bond is indeed polar due to the difference in electronegativity between carbon (2.5) and chlorine (3.0), the overall molecule has no net dipole moment. This occurs because of the molecule's symmetrical geometry, which causes the individual bond dipoles to cancel each other out completely.

The key to understanding this lies in combining bond polarity with molecular geometry determined by VSEPR theory. $\ce{CCl4}$ has a tetrahedral shape with the carbon atom at the center and four chlorine atoms positioned at the corners of a tetrahedron, giving bond angles of $109.5\degree.$ In this perfectly symmetrical arrangement, each $\ce{C-Cl}$ bond dipole points from the carbon toward a chlorine atom. However, because these four dipoles are oriented symmetrically in three$-$dimensional space, they cancel out when added as vectors. Think of it like four people pulling equally on ropes attached to a central point from the corners of a square platform; the net force would be zero. This demonstrates an important principle: molecular polarity depends not just on whether individual bonds are polar, but on how those bond dipoles are arranged in space. A molecule is only polar if its bond dipoles don't cancel out, resulting in a net dipole moment.