$12 \ g$ of urea is dissolved in $1 \ L$ of water and $68.4 \ g$ of sucrose is dissolved in $1 \ L$ of water. The lowering of vapour pressure of the first case is

$A$ 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 $:$

$A$ 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 $298 \,K$

If $x \ g$ of a non-volatile,non-electrolytic solute is dissolved in $114 \ g$ of octane to reduce its vapour pressure to $80 \%$ of that of pure octane,then $x$ is ........... $g$. (Molar mass of solute $= 40 \ g/mol$)

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:

Among acetone,ether,and ethanol,which one will have the maximum and which one will have the minimum vapor pressure?