On adding a solute to a solvent having a vapour pressure of $0.80 \ atm$,the vapour pressure reduces to $0.60 \ atm$. The mole fraction of the solute is:

Which of the following sets of variables gives a straight line with a negative slope when plotted? ($P =$ vapour pressure,$T =$ Temperature in $K$)

$A$ solution containing $30 \,g$ of non-volatile solute in $90 \,g$ of water has a vapour pressure of $2.8 \,kPa$ at $298 \,K$. Further,$18 \,g$ of water is added to the solution and the new vapour pressure becomes $2.9 \,kPa$ at $298 \,K$. Calculate:
$i$. Molar mass of the solute
$ii$. Vapour pressure of water at $298 \,K$

The vapour pressure lowering caused by the addition of $100 \, g$ of sucrose (molecular mass $= 342$) to $1000 \, g$ of water if the vapour pressure of pure water at $25 \, ^oC$ is $23.8 \, mm \, Hg$.

$60 \ g$ of Urea (Mol. wt $60$) was dissolved in $9.9 \ moles$ of water. If the vapour pressure of pure water is $P_o$,the vapour pressure of the solution is: (in $P_o$)

$A$ solution is made by mixing $1 \ mole$ of volatile liquid $A$ with $3 \ moles$ of volatile liquid $B$. The vapour pressure of pure $A$ is $200 \ mm \ Hg$ and that of the solution is $500 \ mm \ Hg$. The vapour pressure of pure $B$ and the least volatile component of the solution,respectively,are $:$