Van der Waals interactions make the given compound exist as a liquid under normal temperature and pressure        conditions.

Van der Waals interactions are weak forces of attraction between molecules. They occur when temporary fluctuations in the electron distribution around an atom induce a temporary partial charge on a neighboring atom. This induces a corresponding shift in the second atom's electron cloud, leading to a temporary dipole. These temporary dipoles induce further dipoles in neighboring atoms, leading to a chain reaction. The cumulative effect of these temporary dipoles leads to an overall attraction between molecules, known as a Van der Waals interaction.

In the context of a compound existing as a liquid under normal temperature and pressure conditions, Van der Waals interactions play a crucial role. For a substance to exist as a liquid, the intermolecular forces of attraction must be strong enough to hold the molecules together, but not so strong as to lock them into a rigid structure (as in a solid). Van der Waals interactions, being relatively weak, are often just right for this. They allow the molecules to move around each other (which is characteristic of a liquid state) while still keeping them close together.

Therefore, if a compound exists as a liquid under normal conditions, it is likely that Van der Waals interactions are the dominant intermolecular force.