What are Van der Waal forces ?

Van der Vaal forces are temporarily induced dipole forces. At any given time, the density of electrons in 1 atom will repel the electrons in another closely located atom, creating a dipole. Van der waal forces are the weakest type of interaction between molecules and exist in every compound, as every atom has electrons. Despite being weak interactions, in large molecules with lots of electrons, they can be significant. For example, van der waal forces are significant in hydrocarbons such as alkanes as there are no other interactions such as hydrogen bonds and dipole forces due to polarity.