Question

Which of the following 0.1 M aqueous solution exhibits highest osmotic pressure at 25°C?

• A. Urea
• B. CoCl\(_2\)
• C. KCl
• D. Glucose

Hint:

Osmotic pressure increases with the van't Hoff factor (\(i\)), which represents the number of ions or particles formed upon dissociation.

Answer 1

The Correct Option is B

Step 1: Understanding osmotic pressure.
Osmotic pressure (\(\Pi\)) is given by the formula: \[ \Pi = i \cdot M \cdot R \cdot T \] Where: - \(i\) is the van't Hoff factor (the number of particles the solute dissociates into) - \(M\) is the molarity of the solution - \(R\) is the ideal gas constant - \(T\) is the temperature in Kelvin Step 2: Analyzing the options.
(A) Urea: Urea does not dissociate into ions, so its \(i\) value is 1.
(B) CoCl\(_2\): Cobalt chloride dissociates into 3 ions (Co\(^{2+}\) and 2 Cl\(^-\)), so its \(i\) value is 3.
(C) KCl: KCl dissociates into 2 ions (K\(^+\) and Cl\(^-\)), so its \(i\) value is 2.
(D) Glucose: Glucose does not dissociate into ions, so its \(i\) value is 1.
Step 3: Conclusion.
CoCl\(_2\) will exhibit the highest osmotic pressure because it dissociates into the most particles. Thus, the correct answer is (B) CoCl\(_2\).