The effect of pressure on the solubility of a gas in a
particular liquid at constant temperature can be readily understood in terms of
Henry’s law which states that,
“At constant temperature, the mass of a gas dissolved
in a unit volume of a liquid is directly proportional to the pressure of the
gas above the liquid at equilibrium.”
Mathematically,
m ∝ p
Or, m = k p
Where, m is the mass of the gas dissolved by
unit volume of solvent,
P is the pressure of the gas in equilibrium with the solution
K is a proportionality constant known as Henry’s Law constant.
Applicability
of Henry’s Law
For the strict applicability of Henry’s Law:
- Temperature should be high
- Pressure should be low
- No chemical reaction should take place between the dissolved gas and the solvent (such as compound formation or association)
