Final answer:
Acetonitrile forms interfacial dipoles when it comes into contact with a grounded surface, the strength of which is significant due to its polar nature. The strength can be inferred from acetonitrile's high boiling point. Increasing temperature can overcome the dipole interactions as it increases the molecular kinetic energy.
Step-by-step explanation:
When acetonitrile, a polar solvent, comes into contact with a grounded surface in air, interfacial dipoles are indeed formed due to the interaction of the acetonitrile molecules with the surface and the surrounding air. Acetonitrile has a significant dipole moment as the carbon in the nitrile group has a triple bond with nitrogen, causing a separation of charges within the molecule.
This polarity will cause the molecules to align with the partial positive and negative charges interacting with the surface and air respectively.
The strength of the dipole interaction will depend on the specific orientation and arrangement of the acetonitrile molecules at the interface. These intermolecular forces can be measured in debye units or compared qualitatively in terms of how they affect properties like boiling points. For acetonitrile, which has a higher boiling point due to these interactions, the strength is significant.
To overcome these interfacial dipole interactions and cause disorientation, you would generally need to increase the kinetic energy of the molecules, which can be achieved by raising the temperature. The higher the temperature, the more likely the thermal motion will overcome the dipole interactions, disrupting the molecule's preferred orientation at the surface.