According to Raoult's law,the relative lowering of vapour pressure for a solution is equal to which of the following?

Two liquids $X$ and $Y$ form an ideal solution. At a constant temperature of $300 \ K$,the vapor pressure of a solution containing $1 \ mol$ of $X$ and $3 \ mol$ of $Y$ is $550 \ mm \ Hg$. If $1 \ mol$ of $Y$ is added to this solution,the vapor pressure of the solution increases by $10 \ mm \ Hg$. What are the vapor pressures of $X$ and $Y$ in their pure states?

When $1 \ g$ of urea is dissolved in $50 \ g$ of water,the relative lowering of vapour pressure of the solution is equal to the relative lowering of vapour pressure of a solution formed by dissolving glucose in the same amount of water. How many grams of glucose were dissolved?

$A$ solution is prepared by mixing $8.5 \ g$ of $CH_2Cl_2$ and $11.95 \ g$ of $CHCl_3$. If the vapour pressures of pure $CH_2Cl_2$ and $CHCl_3$ at $298 \ K$ are $415 \ mm \ Hg$ and $200 \ mm \ Hg$ respectively,the mole fraction of $CHCl_3$ in the vapour phase is: (Molar mass of $Cl = 35.5 \ g \ mol^{-1}$)

When a non-volatile solute is added to a pure solvent,the vapor pressure decreases by $11.5 \ torr$. If the mole fraction of the solute is $0.2$,what will be the vapor pressure of the pure solvent in $torr$?

The vapour pressures of pure liquids $A$ and $B$ are $400$ and $600\, mm\, Hg$,respectively at $298\, K$. On mixing the two liquids,the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid $B$ is $0.5$ in the mixture. The vapour pressure of the final solution,the mole fractions of components $A$ and $B$ in vapour phase,respectively are