Effect of Pressure on Solubility — Henry's Law

Pressure and Solubility

Pressure only affects the solubility of gases, not liquids or solids.

Henry's law is used to describe the relationship between solubility of gasses and pressure: $$Solubility\ =\ k \times P$$ In the equation, $k$ is the Henry's law constant which has a specific value for different gasses, $P$ describes the pressure of the gas. The solubility is directly related to the pressure. As pressure increases, solubility increases by the same amount.

Gas Solubility Example

Let's consider a can of soda! When the can is opened, bubbles come out from the soda. This occurs because the pressure of $CO_2$ gas in the can decreases when it is opened. This causes the gas to become less soluble. A bottle of opened soda can remain carbonated for some time if closed and left in a cold space. However, the pressure of the bottle will never be like that of the unopened bottle, so eventually it will go flat. Have you ever opened a bottle or can of soda and it shoots out? This can occur if the pressure inside is increased due to shaking or added heat. The pressure change when opened is much greater. This causes the gas to escape the liquid so violently that the gas pushes liquid out as well.

(Video) Pressure and Gas Solubility (Henry's Law)

by Tyler DeWitt

In this video, Tyler DeWitt explains the connection between gas pressure and solubility. He illustrates the principles with two examples: soda and scuba divers. This video is a great explanation!