Question

2 g mixture of glucose and sucrose is dissolved in 1 litre water at 298 K to develop an osmotic pressure of 0.207 atm. Calculate percentage composition of glucose and sucrose by mole as well as by mass.

Answer 1

Let (x)g be glucose and (2-x) g be sucrose

$\Pi$ =CRT

0.207=$(\frac{x}{180\times 1}+\frac{2-x}{342\times 1}$) $\times$298

$\frac{x}{180}+\frac{2-x}{342}$ =0.0084

Solving for x , we get x=0.97g

weight of glucose= 0.97 g , weight of sucrose = 1.03g

moles of glucose =$\frac{0.97}{180}$ =5.38$\times {10}^{-3}$

moles of sucrose= $\frac{1.03}{342}$ = 3.01$\times {10}^{-3}$