Which term describes a solution whose concentration is expressed as moles per liter?

• A. Molarity
• B. Solute
• C. Dilution
• D. Reagent water

Answer: (A)

Molarity is the term for concentration expressed as moles of solute per liter of solution. It’s defined as moles of solute divided by liters of solution (M = moles/volume in liters). This unit directly ties the amount of a substance to the volume of the solution, which is why it’s widely used in chemistry calculations. Temperature can impact molarity because volume changes with temperature. The other terms refer to different ideas: a solute is what’s dissolved, dilution is the process of making a solution less concentrated by adding solvent, and reagent water is water used as the solvent. So the description of a solution whose concentration is expressed as moles per liter points to molarity.