Which of the following is a property that molarity provides, but percent solution does not?

• A. The total volume of the solvent used
• B. The mass of solute present in 100 g of solution
• C. The exact number of moles of solute per liter of solution
• D. The density of the solution

Answer: (C)

Verified step by step guidance

1. Understand the definitions of molarity and percent solution: Molarity (M) is defined as the number of moles of solute per liter of solution, while percent solution typically refers to the mass or volume of solute per 100 units of solution (mass or volume percent).
2. Recognize that percent solution gives a ratio based on mass or volume but does not directly provide the number of moles of solute, which depends on the molar mass of the solute.
3. Note that molarity explicitly provides the concentration in terms of moles per liter, which is a direct measure of the amount of substance in a given volume of solution.
4. Compare the options: total volume of solvent, mass of solute in 100 g solution, density, and exact moles per liter. Only molarity gives the exact number of moles of solute per liter of solution.
5. Conclude that the unique property provided by molarity, but not by percent solution, is the exact number of moles of solute per liter of solution.