According to Raoult's law,the relative lowering of vapour pressure of a solution of a non-volatile solute is equal to:

$A$ solution was prepared by dissolving $0.1 \ mol$ of a nonvolatile solute in $0.9 \ mol$ of water. What is the relative lowering of vapour pressure of the solution?

The vapour pressure of a solvent decreases by $2.5 \ mm \ Hg$ by adding a solute. What is the mole fraction of solute? (Vapour pressure of pure solvent is $250 \ mm \ Hg$)

In a mixture of liquids $A$ and $B$, if the mole fractions of component $A$ in vapour phase and liquid mixture are $x_1$ and $x_2$ respectively, then the total vapour pressure of liquid mixture is (where $P_{A}^{\circ}$ and $P_{B}^{\circ}$ are the vapour pressures of pure $A$ and $B$)

An aqueous solution is $1.00 \ molal$ in $KI$. Which change will cause the vapour pressure of the solution to increase?

The vapour pressure of water is $12.3 \, kPa$ at $300 \, K$. Calculate the vapour pressure of a $1 \, molal$ solution of a non-volatile solute in it.