How many grams of solute (molecular weight $60$) are required to be dissolved in $180 \ g$ of water to reduce the vapour pressure to $\frac{5}{6}$ of the pure water?

The variation of vapour pressure $(b)$ as a function of temperature $(a)$ is studied for $C_2H_5OC_2H_5$,$CCl_4$,and $H_2O$ at $760 \ mm \ Hg$ and is shown in the figure below. The boiling temperatures of $C_2H_5OC_2H_5$,$CCl_4$,and $H_2O$ are $308 \ K$,$350 \ K$,and $373 \ K$ respectively. Curves $A$,$B$,and $C$ respectively correspond to:

What is the vapor pressure of a solution containing a solid solute and a liquid solvent?

Lowering of vapour pressure due to a solute in $1 \, molal$ aqueous solution at $100 \, ^\circ C$ is ........ $torr$.

What is the mass in $g$ of a non-volatile solute with a molecular weight of $40$ that should be dissolved in $57 \ g$ of octane to reduce its vapour pressure to $80 \%$ of its original value?

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