Question

You are given two aqueous solutions containing different ionic solutes (Solution A and Solution B). What if you are told that Solution A has a greater concentration than Solution B by mass percent, but Solution B has a greater concentration than Solution A in terms of molality? Is this possible? If not, explain why not. If it is possible, provide example solutes for A and B, and justify your answer with calculations.

Short answer

Yes, it is possible to have Solution A a greater concentration than Solution B by mass percent, but Solution B has a greater concentration than Solution A in terms of molality.

Step-by-step solution

Molality of the solution:

Mass percent$=\left(\frac{\text{grams of solute}}{\text{grams of solution}}\right)\times 100$

Molality$=\frac{\text{moles of solute}}{\text{kilograms of solvent}}$

Solute concentration:

If Solution A has greater concentration of solute it is possible.An example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.