What mass of solute (molar mass $58 \mathrm{~g} \mathrm{~mol}^{-1}$) is to be dissolved in $2.5 \mathrm{~dm}^3 \mathrm{~H}_2 \mathrm{O}$ to generate osmotic pressure of 0.245 atm at 300 K ?

$$\left(\mathrm{R}=0.0821 \mathrm{~dm}^3 \text { atm } \mathrm{K}^{-1} \mathrm{~mol}^{-1}\right)$$

Which of the following equation correctly represents molar mass of a solute by knowing boiling point elevation?

A solution of non volatile solute has boiling point elevation 1.75 K . Calculate molality of solution $\left[\mathrm{K}_{\mathrm{b}}=3.5 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$

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 $=342 \mathrm{~g} \mathrm{~mol}^{-1}$]