Question

State True or False: Lowering of vapour pressure is proportional to the mole fraction of the solute.
A. True
B. False

Answer 1

The mole fraction can be determined for different components based on the pressure exerted by the formation of vapour. This can be calculated according to Raoult's law which is based on the vapour pressure ${P_{solution}} = {X_{solv}}P_{solv}^0$.

Complete step by step answer:
The vapour pressure of a solute depends on the number of molecules which are mixed in the solution. The number of solute molecules and the solvent molecules mixed with it. The mole fraction of the solute is the ratio of the change in vapour pressure for a given solute with respect to the vapour pressure of water at ${4^o}C$. Therefore, the change in vapour pressure means $\Delta P$ which according to the condition for the mole fraction of a given solute is directly proportional to the changing pressure. The whole condition of the relation between the two conditions can be defined by the given equation.
$\dfrac{{\Delta P}}{P} = X$
Here the changes observed in the vapour pressure of the solute shows that it decreases from its initial level. As it is visible the lowering is similar to that of the mole fraction. Therefore, the statement given here is true that the two physical properties are proportional. Hence the statement about the changes in vapour pressure as compared to the mole fraction being directly proportional is true.

Note:
Changes in vapour pressure is variable according to the number of molecules of the solute and solvent in the given solution. The variable changes in melting and boiling point of the solution take place from the expected value due to vapour pressure.