State Raoult's law for a solution containing volatile components. How does Raoult's law become a special case of Henry's law ?

Explanation

Raoult.s law : It states that for a solution of volatile liquids, the partial vapour pressure of each component in the solution is directly proportional to its mole fraction.
Raoult.s law as a special case of Henry.s law : According to Raoult.s law vapour pressure of a volatile component in a given solution is given by `p_i = x_ip_i^0` In the solution of a gas in a liquid, one of the components is so volatile that it exists as a gas and its solubility is given by Henry.s Law as
`p = K_H x `
where x is the mole fraction of the gas in the solution.
On comparing the equations for Raoult.s law and Henry.s law, it can be seen that partial pressure of the volatile component or gas is directly proportional to mole fraction of that component. Only the proportionality constant `K_H` differs from `p_0^0` Thus Raoult.s law becomes a special case of Henry.s law in which `K_H` becomes equal to `p_i^0`.