Which from the following statements is correct for aqueous solution of $6 \mathrm{~g} \mathrm{~L}^{-1}$ urea and $17 \cdot 12 \mathrm{~g} \mathrm{~L}^{-1}$ of sucrose?

[Molar mass of urea $=60 \mathrm{~g} \mathrm{~mol}^{-1}$

Molar mass of sucrose $=342 \mathrm{~g} \mathrm{~mol}^{-1}$]

Calculate the molar mass of nonvolatile solute when 1.5 g of it is dissolved in 90 g solvent decreases its freezing point by 0.25 K. $$\left[\mathrm{K}_{\mathrm{f}}=1.2 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$$

Identify false statement form following.

Calculate van't Hoff factor of 0.2 m aquesous solution of an electrolyte if it freezes at $-$0.7 K $\left[\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$