If ethanol dissolves in water,then which of the following would be done?

$P$ and $Q$ combine to form two compounds $PQ_2$ and $PQ_3$. If $1 \ g$ of $PQ_2$ is dissolved in $51 \ g$ of benzene, the depression of freezing point is $0.8^{\circ} C$. If $1 \ g$ of $PQ_3$ is dissolved in $51 \ g$ of benzene, the depression of freezing point is $0.625^{\circ} C$. Given $K_f$ of benzene $= 5.1 \ K \ kg \ mol^{-1}$, calculate the atomic masses of $P$ and $Q$.

The elevation in the boiling point of an aqueous urea solution is $0.104 \ K$. What is its $\Delta T_{f}$ (in $K$) value? (Given for water: $K_{b} = 0.52 \ K \ kg \ mol^{-1}$,$K_{f} = 1.86 \ K \ kg \ mol^{-1}$)

$6 \ g$ of a mixture of naphthalene $(C_{10}H_8)$ and anthracene $(C_{14}H_{10})$ is dissolved in $300 \ g$ of benzene. If the depression in freezing point is $0.70 \ K$,the composition of naphthalene and anthracene in the mixture respectively in $g$ are (molal depression constant of benzene is $5.1 \ K \ kg \ mol^{-1}$)

In the depression of freezing point experiment,it is found that the:

$20\%$ 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.]