State henry's law and its application

Henry’s law was first formulated in 1803 by an English physician and chemist William Henry which states that the amount of gas that dissolved in a liquid is directly proportional to the partial pressure of

that gas above the liquid when the temperature is kept constant. The proportionality factor is called Henry’s law constant.

The mathematical formula is given by P ∝ C (or) P = kH.C


P is the partial pressure of the gas in the atmosphere above the liquid

C is the concentration of the dissolved gas

kH is Henry’s law constant of the gas


Henry’s law in Respiration

The main application of Henry’s law in respiratory physiology is that the 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

An everyday example of Henry’s law is given by carbonated soft drinks,

the gas above the 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


Free Class