Henry's Law: A Retrospective.

This article reviews the evolution of Henry's law from its original form as a description of the effect of pressure on the solubility of a gas through a description of the vapor pressure of a volatile solute in dilute solution to a basis of the standard state of a solute. We also relate Henry's law to the properties of regular solutions. We raise the question of whether Henry's law is applicable to any finite concentration and conclude that it is properly only a limiting law in the limit of infinite dilution.