During the depression of freezing point in a solution,which of the following are in equilibrium?

Give the unit of $K_f$.

$1 \ kg$ of $0.75 \ m$ aqueous solution of sucrose is cooled to $-4^{\circ} C$. The amount of ice (in $g$) that will be separated out is .... . (Nearest integer)
Given: $K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1}$

Which of the following solutions has the highest freezing point?

What is the depression of freezing point,when mole fraction of non-electrolyte solute in aqueous solution is $0.01$ (in $K$)? ($K_f$ of $H_2O = 1.86 \ K \ kg \ mol^{-1}$)

$A$ solution of a nonvolatile solute is obtained by dissolving $1 \ g$ in $100 \ g$ of solvent,which decreases its freezing point by $0.3 \ K$. Calculate the cryoscopic constant of the solvent if the molar mass of the solute is $60 \ g \ mol^{-1}$.