Respuesta :

B. P-Cl

Explanation

A molecule that has dipole intermolecular forces has to be polar. In other words, only polar molecules can engage in dipole-dipole interactions. For a molecule to be polar, it has have a non-zero net dipole.

For that, it should contain polar bonds that provide the dipole moment. A bond is polar if it connects atoms of two different elements. For example, C-H is polar but H-H is not. So is that case with double bonds such as C=O, which is also polar.

In case there are more than one polar bond in a single molecule, dipole from each of those bonds will add as if they are vectors. They could well balance each other if they have equal strengths, and are placed symmetrically. For example, C=O bonds in molecule C are polar. Each one of them carries a dipole moment. However, the two C=O bonds in the molecule are directed at each other. Their dipole moments have the same strength. However, they balance each other out within the molecule. The molecule will have no net dipole. As a result, it has no dipole-dipole interactions.

The only bond in molecule A is nonpolar. It has no dipole moment and no net dipole. As a result, it has no dipole-dipole interactions.

The P-Cl bond in molecule B is polar. There's no other polar bond (no other bond at all) to balance the dipole moment of that P-Cl bond. The molecule has a net dipole, is polar, and have dipole intermolecular forces.

As mentioned above, molecule C is nonpolar. It has dipole-dipole intermolecular forces.

Dipole moments due to the C-H bonds balance out each other in molecule D. The molecule will be nonpolar. It has no dipole-dipole intermolecular forces.