Question

The following solutions were prepared by dissolving $10 g$ of glucose $\left( C _{6} H _{12} O _{6}\right)$ in $250 \,ml$ of water $\left( P _{1}\right)$ $10 \,g$ of urea $\left( CH _{4} N _{2} O \right)$ in $250 \,ml$ of water $\left( P _{2}\right)$ and $10 g$ of sucrose $\left( C _{12} H _{22} O _{11}\right)$ in $250\, ml$ of water $\left( P _{3}\right)$. The right option for the decreasing order of osmotic pressure of these solutions is:

• A. $P _{2}> P _{1}> P _{3}$
• B. $P _{1}> P _{2}> P _{3}$
• C. $P _{2}> P _{3}> P _{1}$
• D. $P _{3}> P _{1}> P _{2}$

Answer 1

Answer: (A)

$P _{2}> P _{1}> P _{3}$

Answer 2

$\pi=\frac{W}{M} S T$ $\pi \propto \frac{1}{\text { Mol.wt }}$ Glucose $(180)$, Urea $(60)$, Sucrose $(342)$ $\pi_{\text {urea }}>\pi_{\text {glucose }}>\pi_{\text {sucrose }}$ $P_{2}>P_{1}>P_{3}$