What does molarity measure in a solution?

• A. Volume of solute per liter of solution
• B. Number of moles of solute per liter of solution
• C. Moles of solute per milliliter of solution
• D. Concentration of solvent in the solution

Answer: (B)

Molarity measures the concentration of a solution in terms of the number of moles of solute present per liter of solution. This concept is essential in chemistry because it allows for the quantification of how much solute is dissolved in a specific volume of solvent, facilitating calculations and reactions in laboratory settings. Molarity is commonly expressed in units of moles per liter (mol/L), which provides a clear and standardized way to describe the concentration of the solute in the solution.

Understanding that molarity is specifically related to the number of moles allows chemists to predict how different concentrations can influence reactions and to accurately prepare solutions for experiments. This measurement is crucial when diluting solutions or when performing stoichiometric calculations in chemical reactions.

The other options do not accurately describe molarity; one mentions volume of solute directly, another looks at moles per milliliter, and one refers to the concentration of the solvent, which is not what molarity specifically represents.