When an aqueous solution freezes at its freezing point,which components are in equilibrium?

Two elements $A$ and $B$ form compounds with molecular formulas $AB_2$ and $AB_4$. When $1 \ g$ of $AB_2$ is dissolved in $20 \ g$ of $C_6H_6$,the freezing point decreases by $2.3 \ K$. When $1 \ g$ of $AB_4$ is dissolved in $20 \ g$ of $C_6H_6$,the freezing point decreases by $1.3 \ K$. The molal depression constant for benzene is $5.1 \ K \ kg \ mol^{-1}$. Calculate the atomic weights of $A$ and $B$.

Calculate the freezing point of a solution prepared by dissolving $1.8 \ g$ of glucose $(C_6H_{12}O_6)$ in $500 \ g$ of water. The $K_f$ value for water is $1.86 \ K \ kg \ mol^{-1}$. (in $K$)

Which aqueous solution has the minimum freezing point?

The mass of urea required to be dissolved in $500 \ mL$ of water to produce a depression in freezing point of $0.186 \ ^oC$ is ........ $g$. $(K_f = 1.86 \ ^oC/m)$

How many grams of glucose must be added to $1 \ L$ of water such that the value of $\frac{\Delta T_f}{K_f}$ becomes $\frac{1}{1000}$?