Question

Among equimolal solutions of MgCl₂, NaCl, FeCl₃ and C₁₂H₂₂O₁₁, which will show minimum osmotic pressure? Why?

Answer 1

C₁₂H₂₂O₁₁

Explanation:

Osmotic pressure is given by 

π = i CRT 

In this equation, i represents the van’t Hoff factor, which indicates the number of particles produced by a solute in solution.

C₁₂H₂₂O₁₁ (sucrose) is a non-electrolyte, so i is 1.

NaCl → i = 2, MgCl₂ → i = 3, FeCl₃ → i = 4

Since sucrose produces the fewest particles, it has the lowest osmotic pressure among equimolal solutions.