Question

What is Raoult's law? How ideal solution obey this law?

Answer 1

Raoult’s law

• This law was given by the French chemist François-Marie Raoult in 1887.
• For a solution of volatile liquids, the partial vapor pressure of each component $\left(p_1\right)$ of the solution is directly proportional to its mole fraction present in solution $\left(x_1\right)$.
• The expression is as follows

$p_1=p_1^{\circ }{x}_1$

• Here, $p_1^{\circ }$ is the partial vapor pressure of pure component 1 at the same temperature values.

Ideal solution

• Ideal solution refers to the solution of a mixture whose thermodynamic properties are the same as that of the solute and the solvent.
• When the enthalpy of mixing of a solution becomes zero, the solution behaves as an ideal solution.
• Ideal solution follows Raoult's law, as it takes the same energy for solvent molecules to move away from its surface as the pure solvent does, and the force of attraction between the solute-solute and solvent-solvent is the same as that between the solute-solvent in the solution.