Question

Arrange the following solutions as directed: 

0.1 M urea, 0.1 M NaCl, 0.1 M BaCl₂, 0.1 M K₄Fe(CN)₆ (in the order of increasing osmotic pressure)

Explain the reason for your answers also.

Answer 1

0.1 M urea < 0.1 M NaCl < 0.1 M BaCl₂ < 0.1 M K₄Fe(CN)₆

Reason:

Osmotic pressure is a colligative property that depends on the number of solute particles. Electrolytes dissociate in solution, increasing the number of particles and thus the osmotic pressure. K₄Fe(CN)₆ gives the most ions, so it exerts the highest osmotic pressure.