A solution of glucose $\left({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\right)$ is isotonic With 4 g of urea $({\mathrm{NH}}_2-\mathrm{CO}-{\mathrm{NH}}_2)$ per litre of solution. The concentration of glucose is :

The osmotic pressure in isotonic solutions is the same.

${\mathrm{iC}}_1\mathrm{RT}={\mathrm{iC}}_2\mathrm{RT}$

identical temperature,

${\mathrm{C}}_1={\mathrm{C}}_2$

$\text{ Conc. of urea }=4\mathrm{g}/\mathrm{L}$

$\begin{array}{l}=\frac{4}{60}\mathrm{mol}/\mathrm{L}\\ =\frac{1}{15}\mathrm{mol}/\mathrm{L}\end{array}$

$\therefore \text{ conc }.\text{ of glucose }=\frac{1}{15}\mathrm{mol}/\mathrm{L}$

$=\frac{180}{15}\mathrm{gm}/\mathrm{L}$

$=12\mathrm{gm}/\mathrm{L}$.