What is the molar mass (in $g \ mol^{-1}$) of a substance,which forms a $7 \%$ by mass solution in water,which freezes at $-0.93^{\circ} C$? ($K_{f}$ of $H_2O = 1.86 \ K \ kg \ mol^{-1}$)

$1.8 \ g$ of fructose is added to $2 \ kg$ of water. The freezing point of the solution is $(k_f = 1.86 \ K \ kg \ mol^{-1})$ (in $^\circ C$)

How much amount of $NaCl$ should be added to $600 \ g$ of water $(\rho=1.00 \ g / mL)$ to decrease the freezing point of water to $-0.2^{\circ} C ?$ ............. $gm$
(The freezing point depression constant for water $=2 \ K \ kg \ mol^{-1}$ )

What is the value of $K_{f}$ if $30 \ g$ urea (molar mass $60$) dissolved in $0.5 \ dm^{3}$ of water decreases the freezing point by $0.15^{\circ}C$?

$1 \ kg$ 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: $K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1}$

What happens to the freezing point of benzene when a small quantity of naphthalene is added to it?