Liquids take the shape of the container they are in but do not necessarily occupy the entire volume. The molecules of a liquid do not move as quickly as the molecules of a gas and are generally held in place by additional weak bonding interactions. These additional bonds include dipole interactions, hydrogen bonding, and van der Waals forces. Dipole interactions occur between molecules with polar bonds. Since molecules with polar bonds are slightly charged, having both a positive and a negative end, the positive end of one molecule is attracted to the negative end of a nearby molecule. A special case of the dipole interaction is hydrogen bonding. Since a hydrogen atom is essentially a proton, its positive nature is attracted to the negative electrons of other atoms (i.e., electrons of atoms the hydrogen is not bonded to). Hydrogen atoms can experience this type of bond only with nitrogen, oxygen, fluorine, and chlorine. Van der Waals forces occur between molecules that have a nuetral charge distribution or non-polar molecules. The forces arise from the fact that even in a molecule with a nuetral charge distribution, there can be a moment when charge is distributed unevenly around the molecule. Such imbalances in electron density induce warping of the electron clouds of other nearby molecules to create an attractive force. The Van der Waals forces increase with the mass of the molecule.
If two liquids can mix together (water and alcohol for example), they are miscible. If they remain separate even after being placed in a container together (water and oil),
