The unit of measurement for the concentration of a solution is typically expressed in molarity (M), which indicates the number of moles of solute per liter of solution. Molarity allows scientists and chemists to quantify the exact amount of substance in a given volume of liquid, facilitating calculations in chemical reactions and dilutions. Other units may include % concentration (weight/volume or volume/volume) and molality (moles of solute per kilogram of solvent). Accurate measurement of concentration is critical in various fields, including pharmacology, biochemistry, and environmental science, as it influences reaction rates and outcomes.