At $80\,^oC$,the vapour pressure of pure liquid $A$ is $520\, mm\,Hg$ and that of pure liquid $B$ is $1000\, mm\,Hg$. If a mixture of $A$ and $B$ boils at $80\,^oC$ and $1\, atm$ pressure,the amount of $A$ in the mixture is ........... $mol\,\%$.

Assertion : Lowering of vapour pressure is directly proportional to osmotic pressure of the solution.
Reason : Osmotic pressure is a colligative property.

$1 \, \text{mole}$ of each of $A$ and $B$ form an ideal solution of vapour pressure $100 \, \text{mm Hg}$. Addition of $2 \, \text{moles}$ of $B$ to it decreases the vapour pressure by $20 \, \text{mm Hg}$. The vapour pressure of $A$ and $B$ in pure state are,respectively:

If the mole fraction of the solvent decreases while preparing a solution,then ...........

Select the correct statement for an ideal solution of a non-volatile solute in a liquid solvent.

$20\%$ of acetic acid is dissociated when its $5\ g$ is added to $500\ mL$ of water. The depression in freezing point of such water is $..... \times 10^{-3} \ { }^{\circ}C$. Atomic mass of $C$,$H$,and $O$ are $12$,$1$,and $16 \ \text{a.m.u.}$ respectively.
[Given: Molal depression constant and density of water are $1.86 \ K \ kg \ mol^{-1}$ and $1 \ g \ cm^{-3}$ respectively.]