Question

If the osmotic pressure of a 0.010 M aqueous solution of sucrose at 27$^\circ$C is 0.25 atm, then the osmotic pressure of a 0.010 M aqueous solution of NaCl at 27$^\circ$C is

• A. 0.062 atm
• B. 0.12 atm
• C. 0.25 atm
• D. 0.50 atm

Hint:

Electrolytes increase osmotic pressure due to dissociation.

Answer 1

The Correct Option is D

Understanding the Concept: \[ \pi = iCRT \]

Step 1: For sucrose, $i = 1$ (non-electrolyte).

Step 2: For NaCl, $i \approx 2$ (Na$^+$ + Cl$^-$).

Step 3: Osmotic pressure $\propto$ $i$.

Step 4: Therefore, \[ \pi_{\text{NaCl}} = \textcolor{red}{2 \times 0.25 = 0.50\ \text{atm}} \] Final Answer:
Osmotic pressure = 0.50 atm