Of the following $0.10 \ m$ aqueous solutions,which one will exhibit the largest freezing point depression?

The molal elevation constant of water is $0.51 \ K \ kg \ mol^{-1}$. The boiling point of a $0.1 \ m$ aqueous $NaCl$ solution is approximately ......... $^oC$.

When $0.01 \ mol$ of sodium sulphate $(Na_2SO_4)$ is dissolved in $1 \ kg$ of water,complete ionization of the solution is observed. Calculate the decrease in the freezing point of the solution. $(K_f = 1.86 \ K \ kg \ mol^{-1})$

Considering acetic acid dissociates in water,its dissociation constant is $6.25 \times 10^{-5}$. If $5 \ mL$ of acetic acid is dissolved in $1 \ L$ water,the solution will freeze at $-x \times 10^{-2} \ {}^{\circ}C$,provided pure water freezes at $0 \ {}^{\circ}C$.
$x = . . . . . . . . .$ (Nearest integer)
Given: $(K_{f})_{\text{water}} = 1.86 \ K \ kg \ mol^{-1}$.
Density of acetic acid is $1.2 \ g \ mL^{-1}$.
Molar mass of water $= 18 \ g \ mol^{-1}$.
Molar mass of acetic acid $= 60 \ g \ mol^{-1}$.
Density of water $= 1 \ g \ cm^{-3}$.
Acetic acid dissociates as:
$CH_3COOH \rightleftharpoons CH_3COO^{-} + H^{+}$

$pH$ of a $0.1 \ M$ monobasic acid is found to be $2$. Hence its osmotic pressure at a given temperature $T \ K$ is (in $RT$)

Observe the following statements:
Statement-$I$: The boiling point of $0.1 \ M$ urea solution is less than that of $0.1 \ M$ $KCl$ solution.
Statement-$II$: Elevation of boiling point is inversely proportional to molar mass of solute.
The correct answer is: