Editing Solution (chemistry) (section)

== Liquid solution characteristics==

{{See also|Solvent#Solvent classifications}}

In principle, all types of liquids can behave as solvents: liquid [[noble gas]]es, molten metals, molten salts, molten covalent networks, and molecular liquids. In the practice of chemistry and biochemistry, most solvents are molecular liquids. They can be classified into [[chemical polarity|polar and non-polar]], according to whether their molecules possess a permanent [[electric dipole moment]]. Another distinction is whether their molecules can form [[hydrogen bond]]s ([[protic]] and aprotic solvents). [[Water]], the most commonly used solvent, is both polar and sustains hydrogen bonds.

[[File:3D model hydrogen bonds in water.svg|thumb|150px|[[Water]] is a good solvent for some polar materials because water molecules are polar and capable of forming hydrogen bonds.]]

Salts dissolve in polar solvents, forming positive and negative ions that are attracted to the negative and positive ends of the solvent molecule, respectively. If the solvent is water, [[Solvation|hydration]] occurs when the charged solute ions become surrounded by water molecules. A standard example is aqueous saltwater. Such solutions are called [[electrolyte]]s. Whenever salt dissolves in water [[ion association]] has to be taken into account.

Polar solutes dissolve in polar solvents, forming polar bonds or hydrogen bonds. As an example, all alcoholic beverages are [[aqueous solution]]s of [[ethanol]]. On the other hand, non-polar solutes dissolve better in non-polar solvents. Examples are hydrocarbons such as [[oil]] and [[petroleum|grease]] that easily mix, while being incompatible with water.

An example of the immiscibility of oil and water is a leak of petroleum from a damaged tanker, that does not dissolve in the ocean water but rather floats on the surface.