Explanation:

A dipole moment is the measure of the separation of positive and negative charges in a molecule. It is a vector quantity and has both magnitude and direction. When the molecule has a polar covalent bond, it has a dipole moment. If the bond dipoles cancel out each other, then the molecule is nonpolar, and its dipole moment is zero.

The given compounds are:

a) CCl4
b) CH3Cl
c) CHI3
d) CHCl3

Now, let's analyze each compound based on its molecular geometry and bond polarity to determine its dipole moment.

a) CCl4:

CCl4 has a tetrahedral molecular geometry with four C-Cl bonds arranged symmetrically around the central carbon atom. The C-Cl bond is polar covalent, with chlorine being more electronegative than carbon. However, due to the symmetry of the molecule, the bond dipoles cancel out each other, resulting in a net dipole moment of zero. Therefore, CCl4 has zero dipole moment.

b) CH3Cl:

CH3Cl has a trigonal pyramidal molecular geometry with three C-H bonds and one C-Cl bond. The C-Cl bond is polar covalent, with chlorine being more electronegative than carbon. The three C-H bonds are also polar covalent, with carbon being more electronegative than hydrogen. However, due to the asymmetrical arrangement of the bonds, the bond dipoles do not cancel out each other, resulting in a net dipole moment. Therefore, CH3Cl has a dipole moment.

c) CHI3:

CHI3 has a tetrahedral molecular geometry with three I-H bonds and one I-C bond. The I-C bond is polar covalent, with iodine being more electronegative than carbon. The three I-H bonds are also polar covalent, with iodine being more electronegative than hydrogen. However, due to the symmetry of the molecule, the bond dipoles cancel out each other, resulting in a net dipole moment of zero. Therefore, CHI3 has zero dipole moment.

d) CHCl3:

CHCl3 has a tetrahedral molecular geometry with three C-H bonds and one C-Cl bond. The C-Cl bond is polar covalent, with chlorine being more electronegative than carbon. The three C-H bonds are also polar covalent, with carbon being more electronegative than hydrogen. However, due to the asymmetrical arrangement of the bonds, the bond dipoles do not cancel out each other, resulting in a net dipole moment. Therefore, CHCl3 has a dipole moment.

Conclusion:

Among the given compounds, CCl4 has zero dipole moment because the bond dipoles cancel out each other due to the symmetrical arrangement of the bonds around the central atom.