For a binary solution, when a nonvolatile nonelectrolyte solute is dissolved in a solvent, the vapour pressure of the solvent decreases by $20 \%$. What is the mole fraction of the solvent in the solution?

At $298 \ K$,the vapour pressure of a solution of $7.5 \ g$ of non-volatile solute in $90 \ g$ of water is $2.8 \ kPa$. If $18 \ g$ of water is added to this solution,the vapour pressure becomes $2.81 \ kPa$ at the same temperature. The molar mass of the solute in $g \ mol^{-1}$ is:

In an experiment, $1 \ g$ of a non-volatile solute was dissolved in $100 \ g$ of acetone (molar mass $= 58 \ g/mol$) at $298 \ K$. The vapour pressure of the solution was found to be $192.5 \ mm \ Hg$. Calculate the molecular weight of the solute. (Vapour pressure of pure acetone $= 195 \ mm \ Hg$) (in $g/mol$)

Calculate the mass of a non-volatile solute (molar mass $40 \, g \, mol^{-1}$) which should be dissolved in $114 \, g$ octane to reduce its vapour pressure to $80 \%$.

Vapour pressure of solvent $A$ is $0.90 \text{ atm}$. When a non-volatile solute is added,the vapour pressure drops to $0.60 \text{ atm}$. What is the mole fraction of $A$ in the solution?

Dry air was drawn through bulbs containing pure water,then through bulbs containing a solution of $600 \ g$ of a non-electrolyte in $360 \ g$ of water at the same temperature,and finally through a tube in which dried $CaCl_2$ was placed. The solution bulb gained $1.5 \ g$ and the dried $CaCl_2$ gained $2 \ g$. The molecular mass of the solute is: