Question

If osmotic pressure of 0.2 M aqueous glucose solution is 5 atm at 300 K. Calculate the concentration of glucose solution having osmotic pressure 2.5 atm at same temperature.

• A. 0.1 M
• B. 0.05 M
• C. 0.75 M
• D. 0.25 M

Answer 1

Answer: (A)

0.1 M

Answer 2

Given the osmotic pressure formula:

$$\pi = MRT$$

For glucose, the van’t Hoff factor $i = 1$. Thus, osmotic pressure is directly proportional to the concentration:

$$\frac{\pi_1}{\pi_2} = \frac{M_1}{M_2}$$

Substitute the given values:

$$\frac{5\, \text{atm}}{2.5\, \text{atm}} = \frac{0.2\, \text{M}}{M_2}$$

This simplifies to:

$$2 = \frac{0.2}{M_2} \quad \Longrightarrow \quad M_2 = \frac{0.2}{2} = 0.1\, \text{M}$$