Question

Which of the following solutions will have the highest osmotic pressure?

• A. 0.1 M \( KCl \)
• B. 0.1 M \( CaCl_2 \)
• C. 0.1 M Glucose
• D. 0.1 M Urea

Hint:

For questions comparing colligative properties, always look for the solute that produces the maximum number of ions upon dissociation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Osmotic pressure (\( \pi \)) is a colligative property, which means its value depends on the number of solute particles (ions or molecules) in the solution.
Step 2: Detailed Explanation:
We evaluate the number of particles \( i \) produced by each solute:
(A) \( KCl \rightarrow K^+ + Cl^- \); \( i = 2 \).
(B) \( CaCl_2 \rightarrow Ca^{2+} + 2Cl^- \); \( i = 3 \).
(C) Glucose is a non-electrolyte; \( i = 1 \).
(D) Urea is a non-electrolyte; \( i = 1 \).
Since \( CaCl_2 \) dissociates into the maximum number of ions (3 ions), it will have the highest effective concentration of particles and thus the highest osmotic pressure.
Step 3: Final Answer:
The solution with the highest osmotic pressure is 0.1 M \( CaCl_2 \).