It states that partial pressure of the solute gas is proportional to a mole fraction of that component in liquid phase but proportionality constant is H
pA = H* xA=YA . P
where
- pA = equilibrium partial pressure of pure liquid 'A'
- H = Henry's law constant for A in specific solvents
- xA= mole fraction of A in the liquid phase
- YA = mole fraction of A in the vapor phase
- P = equilibrium pressure
- Henry's law is valid when xA is close to zero that is for a dilute solution of 'A'
Raoult’s law
It states that the equilibrium partial pressure of components 'A' is equal to the product of vapor pressure and mole fraction of 'A' in the liquid phase.
Mathematically
pA = PA0* xA=YA . P
where
- PA0 = vapor pressure of pure liquid A
- Raoult's law is valid when xA is close to 1 that is when the liquid phase is almost pure
