Question

Which of the following units is useful in relating concentration of solution with its vapour pressure?

• A. Mole fraction
• B. Parts per million
• C. Mass percentage
• D. Molality

Answer 1

Answer: (A)

Hint
The number of molecules of a specific component in a mixture divided by the total number of moles in the mixture is known as the mole fraction.
Explanation
Raoult's law states that relative lowering at vapor pressure is proportional to the mole fraction of the solute.
As a result, mole fraction is utilized to relate a solution's concentration to its vapor pressure.
Raoult's law can be expressed as;
$\frac{P^0-P_s}{P^0}=\frac{n_2}{n_1+n_2}=x_2$
Here, $x_2=$ Mole fraction of solute
$n_1=$ Moles of solvent
$n_2=$ Moles of solute
$p_s=$ Vapour pressure of the solution
$p^0=$ Vapour pressure of pure solvent