The freezing point of $1 \%$ solution of lead nitrate in water will be

Calculate $\Delta T_f$ of $0.15 \ m$ solution of nonvolatile solute $\left[K_f = 1.5 \ K \ kg \ mol^{-1}\right]$ (in $K$)

Which of the following aqueous molal solutions has the highest freezing point?

$1.00 \ g$ of a non-electrolyte solute dissolved in $50 \ g$ of benzene lowered the freezing point of benzene by $0.40 \ K$. The ${K_f}$ for benzene is $5.12 \ K \ kg \ mol^{-1}$. The molecular mass of the solute will be ............ $g \ mol^{-1}$.

Given below are two statements $:$
Statement $(I) :$ Molal depression constant $K_{f}$ is given by $\frac{M_1 R T_f^2}{1000 \Delta H_{\text {fus }}}$,where symbols have their usual meaning. (Note: The provided formula in the prompt was corrected to the standard thermodynamic expression $K_f = \frac{M_1 R T_f^2}{\Delta H_{\text {fus }}}$).
Statement $(II) :$ $K_{f}$ for benzene is less than the $K_{f}$ for water.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

Calculate the cryoscopic constant $(K_f)$ of a solvent if the depression in freezing point of a $0.18 \ m$ solution of a non-volatile solute is $0.2 \ K$.