Henry's law states that the partial pressure of a gas in the vapour phase is proportional to a mole fraction of the gas in the solution.
The mathematical formula is: where C= concentration or mole fraction of dissolved gas, KH= Henry's law constant and P= partial pressure of dissolved gas.
Applications:
Henry's law in respiration: The main application of Henry's law in respiratory physiology is that gases will dissolve in the alveoli and bloodstream during gas exchange.
The amount of oxygen that dissolves in the bloodstream is directly proportional to the partial pressure of oxygen in the alveoli air.
Henry's law in carbonated soft drinks: (a) The carbonated drink is almost pure carbon dioxide at a pressure slightly higher than the atmospheric pressure.
When the bottle is opened some of the gas escapes giving a specific pop, this is due to the lower pressure above the liquid and carbon dioxide comes out as bubbles.
It is applied in deep-sea diving as well.
Therefore, Henry's law states the relationship between partial pressure and the concentration of gases.