Determine $\mathrm{i}$(vant-Hoff factor) for a tribasic acid ${\mathrm{H}}_3\mathrm{A}.$ Assuming first dissociation to be $100\%,$ second dissociation $50\%,$ third dissociation $20\%,$ (Round off your answer to nearest integer).

A liquid mixture of $\mathrm{A}$ and $\mathrm{B}$ is placed in a cylinder-and-piston arrangement. The piston is slowly pulled out isothermally, so that the volume of the liquid decreases and that of the vapour increases. At the instant when the quantity of the liquid still remaining is negligibly small, the mole fraction of $\mathrm{A}$ in the vapour phase is$0.4$ ${\mathrm{p}}_{\mathrm{A}}^0=0.4 \mathrm{atm}, {\mathrm{p}}_{\mathrm{B}}^0=1.2 \mathrm{atm}$ at the temperature in question. Calculate the total pressure at which the liquid has almost evaporated. Assume ideal behaviour.

Give answer after multiplying with 100 and rounding off to the nearest integer value.

In an Ostwald-Walker experiment, dry air was first blown through a solution containing a certain amount of solute $(\mathrm{M}=278)$ in $150 \mathrm{g}$ of water and then also through pure water. The loss in mass of water was found to be $0.0827 \mathrm{g}$, while the mass of water absorbed in sulphuric acid was $3.317 \mathrm{g}$. Calculate the amount of the solute.

Give your answer up to two decimal places without rounding-off.

To $500 {\mathrm{cm}}^3$ of water, $3\times {10}^{-3} \mathrm{kg}$ of acetic acid is added. If $23\%$ of acetic acid is dissociated, what will be the depression in freezing point? ${\mathrm{K}}_{\mathrm{f}}$ and density of water are $1.86 \mathrm{K} {\mathrm{kg}}^{-1} {\mathrm{mol}}^{-1}$ and $0.997 \mathrm{g} {\mathrm{cm}}^{-3}$ respectively.

Give answer after multiplying with 100 and rounding off to the nearest integer value.

A solution of a nonvolatile solute in water freezes at $-0.30°\mathrm{C}$. The vapour pressure of pure water at $298 \mathrm{K}$ is $23.51 \mathrm{mm} \mathrm{Hg}$ and ${\mathrm{K}}_{\mathrm{f}}$ for water is $1.86 \mathrm{degree}/\mathrm{molal}$. Calculate the magnitude of change in vapour pressure of this solution $\left(\mathrm{in} \mathrm{mmHg}\right)$ at $298 \mathrm{K}$.

Give answer after multiplying with 100 and rounding off to the nearest integer value.

A $0.1 \mathrm{M}$ solution of an acid (density$=1.01 \mathrm{g}/\mathrm{cc}$ ) is $4.5\%$ ionised. Calculate the depression in fp of the solution. The molecular weight of the acid is $300. {\mathrm{K}}_{\mathrm{f}}=1.86$.

Give answer after multiplying with 100 and rounding off to the nearest integer value.

An aqueous solution of mannitol in water has a vapour pressure of $17.504 \mathrm{mm}$ at $20°\mathrm{C}$, at which temperature the vapour pressure of pure water is $17.535 \mathrm{mm}$. What is the f.p. depression for this solution?

${\mathrm{K}}_{\mathrm{f}}\left({\mathrm{H}}_2\mathrm{O}\right)=1.86$

Give answer after multiplying with 100 and rounding off to the nearest integer value.

$30 \mathrm{mL}$ of methanol (density $=0.7980 \mathrm{g} {\mathrm{mL}}^{-1}$) on mixing with $70 \mathrm{mL}$ of water (density $=0.9984 \mathrm{g} {\mathrm{mL}}^{-1}$) at $298 \mathrm{K}$ gave a solution of density $0.9575 \mathrm{g} {\mathrm{mL}}^{-1}$. Calculate the freezing point of the solution in ${}^{\mathrm{o}}\mathrm{C}$ and report the value by rounding off to two significant figures

${\mathrm{K}}_{\mathrm{f}}\left({\mathrm{H}}_2\mathrm{O}\right)=1.86$

The freezing point of a solution containing $0.2 \mathrm{g}$ of acetic acid in $20.0 \mathrm{g}$ of benzene is lowered by $0.45°\mathrm{C}$. Calculate the degree of association of acetic acid in benzene. ${\mathrm{K}}_{\mathrm{f}}\left({\mathrm{C}}_6{\mathrm{H}}_6\right)=5.12 \mathrm{K} {\mathrm{mol}}^{-1} \mathrm{kg}$.