Chemistry - Liquid Solution Question with Solution | TestHub

Concentration of urea solution, $C_1=\frac{10}{60}$ mol ${\text{dm}}^{-3}$

A $5\%$ solution of the nonvolatile solute means $5$ g of solute is present in $100$ mL (or $0.1$ ${\text{dm}}^3$) of the solution.

Concentration of the nonvolatile solute solution, $C_2=\frac{5}{M\times 0.1}=\frac{50}{M}$ mol ${\text{dm}}^{-3}$

For isotonic solutions, the molar concentrations are equal, so $C_1=C_2$

$\frac{10}{60}=\frac{50}{M}$

$M=\frac{50\times 60}{10}=300$ g ${\text{mol}}^{-1}$

Answer: $300{\text{g mol}}^{-1}$