If the same solute is dissolved in two different solvents to the same concentration and the same temperature, the osmotic pressure ____

Question

will be the same for both.
will be different.
may be the same or different, depending on the solute.
will be lower in the solvent with higher molecular weight.

I don't understand how the colligative properties will vary by solvent through the equation pi=iMRT. Isn't the molarity calculated through moles of solute/ "L of solvent"? However, in reality, this is physically impossible. I think it is the fourth choice, simply because higher molecular weight will cause lower moles of solvent.

Answer 1

If i, M, R, and T are the same, how can pi be any different? However, the problem doesn't state that i is the same; only that the two solvents are different. So how pi varies will depend upon how the solute and solvent interact (how i changes) and that isn't one of the choices. I would pick "none of the above" if given the choice.