Question

What is Raoult’s law? What are its applications?

Answer 1

Hint:
As we know that the solute can be solid, liquid or gas. If we take liquid as solute and liquid as a solvent, then the solutions which we get have different properties than the original properties of solute and solvent. If we take solid as a solute and solvent then the solution which is made has different properties.

Complete step by step solution
Vapour pressure of a solution is the pressure which is exerted by the vapours of solution in equilibrium (rate of evaporation is equal to rate of condensation) at a particular temperature.
According to Raoult’s law, in a solution the vapour pressure of a component at a given temperature is equal to the mole of fraction of that component in the solution multiplied by the vapour pressure of that component in the pure component.
Let us consider a mixture of two completely miscible volatile (easily vaporized) liquids \[A\] and \[B\], having the mole fraction \[{x_A}\] and \[{x_B}\]. Suppose at a certain temperature their partial pressure are \[{p_A}\] and \[{p_B}\] and the vapour pressure in the pure state be \[{p^0}_A\] and \[{p^0}_B\] then according to Raoult's Law:
\[{p_A} = {x_A}{p^0}_A\] and \[{p_B} = {x_B}{p^0}_B\]
Raoult’s law is applicable as:
To measure the lowering of vapour pressure for non-volatile solute.
To measure the strength of bonding of liquids.

Note:
The solution which obeys Raoult’s law is known as the ideal solution (no change in volume on mixing and no change in enthalpy).