How is molarity determined in a solution?

Molarity is a measure of the concentration of a solute in a solution, specifically defined as the number of moles of solute per liter of solution. To determine molarity, one must calculate the moles of solute and then divide that value by the volume of the solution in liters.

Using moles allows us to standardize concentrations based on the amount of substance, while measuring volume in liters provides a consistent unit that is widely used in various scientific calculations. This relationship shows how moles directly relate to the volume of the solution, giving insight into the concentration of the solute present.

The other options do not accurately represent how molarity is calculated. Some suggest inappropriate operations, such as simply dividing mass or incorrectly combining moles and volume without the appropriate ratio required for molarity. Thus, option B precisely captures the correct relationship needed to determine molarity in a solution.