Problem: Is the osmotic pressure of a 0.10 M solution of NaCl greater than, less than, or equal to that of a 0.10 M solution of KBr?

We’re being asked to compare the osmotic pressure of 0.10 M solution of NaCl and 0.10 M solution of KBr. We are given the molarity which we can relate to osmotic pressure.

The osmotic pressure (Π) of a solution is related to the molarity of the solution:

$\boxed{\mathbf{\Pi }\mathbf{=}\mathbf{iMRT}}$

where:

i = van’t Hoff factor

M = molarity of the solution (in M or mol/L)

R = gas constant (0.08206 atm • L/mol • K)

T = temperature