Question

Which one between 0.1 M Urea and 0.1 M NaCl solution will have greater osmotic pressure? Explain the reason.

Hint:

The van’t Hoff factor plays a significant role in determining the osmotic pressure of a solution. More dissociation leads to higher osmotic pressure.

Answer 1

Step 1: Osmotic Pressure Formula
The osmotic pressure (\(\pi\)) is given by the formula: \[ \pi = i M R T \] where, - \(i\) = van’t Hoff factor (number of particles into which a solute dissociates), - \(M\) = molarity of the solution, - \(R\) = universal gas constant, - \(T\) = temperature in Kelvin.
Step 2: Analyze Urea and NaCl
- Urea does not dissociate in water, so \(i = 1\). - NaCl dissociates into two ions: Na\(^+\) and Cl\(^-\), so \(i = 2\).
Step 3: Compare Osmotic Pressure
Given that NaCl dissociates into more particles, the osmotic pressure for NaCl will be higher than that for Urea, even though both have the same molarity. Final Answer: The 0.1 M NaCl solution will have greater osmotic pressure. Correct Answer: (NaCl has higher osmotic pressure)