Choose the correct statement with respect to the vapour pressure of a liquid among the following:

The vapour pressure of benzene at a certain temperature is $640 \ mm$ of $Hg$. $A$ non-volatile and non-electrolyte solid weighing $2.175 \ g$ is added to $39.08 \ g$ of benzene. If the vapour pressure of the solution is $600 \ mm$ of $Hg$,what is the molecular weight of the solid substance?

The vapour pressure of pure benzene at a certain temperature is $0.850 \ bar$. $A$ non-volatile,non-electrolyte solid weighing $0.5 \ g$ when added to $39.0 \ g$ of benzene (molar mass $78 \ g \ mol^{-1}$),the vapour pressure of the solution becomes $0.845 \ bar$. What is the molar mass of the solid substance?

For two components $A$ and $B$,$P_A^0 : P_B^0 = 1:2$ and $X_A : X_B = 1:2$. The mole fraction of $A$ in the vapor phase is:

The vapour pressure of a solvent decreases by $20 \ mm$ of $Hg$ when a non-volatile solute is added to the solvent. The mole fraction of the solute in the solution is $0.5$. What should be the mole fraction of the solvent for the decrease in the vapour pressure to be $10 \ mm$ of $Hg$?

Which of the following changes will cause an increase in the vapour pressure of a $1 \ m$ aqueous $KI$ solution at the same temperature?