Pressure is directly proportional to solubility; an increase in pressure also increases solubility. Conversely, a decrease in pressure also reduces solubility.
In an equilibrium state, solubility pertains to the quantitative measurement of the maximum amount of solute that can be dissolved in a particular amount of solvent. The term "solute" refers to the particle or substance that is dissolved, while "solvent" refers to the component that does the dissolving. The solubility of a material is its concentration in a solution that cannot further dissolve an additional amount of solute.
Several factors affect solubility, including solute and solvent interactions, common -ion effect, pressure and temperature. Pressure does not significantly influence the solubility of solids and liquids. Instead, its effects only become significant on the solubility of gaseous substances.
The relationship between pressure and solubility can be summarized by combining Le Chatelier's principle and Henry's Law. Le Chatelier's principle postulates that when a chemically balanced system is subjected to stress, in this case pressure, the system will change to reduce the stress. Henry's Law states that under constant temperature, the solubility of a gas is correlated to its partial pressure. Henry's Law is represented in the equation, p = kh c, where "p" denotes partial pressure, "kh" indicates Henry's law constant and "c" is the concentration of the dissolved gas. The formula demonstrates the direct relationship of pressure to concentration, as well as solubility. As pressure increases, both the concentration and solubility also increase.