Solution

In chemistry, a solution is one or more substance (the solute) dissolved in another substance (the solvent). A common example would be salt dissolving in water, but gasses may dissolve into liquids, as well as solids into liquids, and liquids and gasses into themselves.

Solvents can be broadly classified into polar? and non-polar solvents. Generally polar or ionic compounds will only dissolve in polar solvents. An excellent test for the polarity of a liquid solvent is to rub a plastic rod, to induce [static electricity]?. Then hold this charged rod close to a running stream of the solvent. If the path of the solvent deviates when the rod is held close to it, it is a polar solvent.

When a solute is dissolved into a solvent, especially polar solvents, a structure forms around it (a process called solvation), which allows the solute-solvent interaction to remain stable.

When no more of a solute can be dissolved into a solvent, the solution is said to be saturated. However the point at which a solution can become saturated changes significantly with different environmental factors, such as temperature, pressure, and contamination.

In general the greater the temperature of a solvent, the more of a given solute it can dissolve. However, some compounds exhibit [reverse solubility]?, which means that as a solvent gets warmer, less solute can be dissolved. Some surfactant?s exhibit this behaviour.

Common solvents

• water - a polar solvent
• ethanol