Normality is defined as what measurement in a solution?

Normality is defined as the concentration of a solution expressed in terms of equivalents of solute per liter of solution. When one considers that an equivalent is typically defined based on the reaction context—such as the number of moles of a reactive species (such as an ion or functional group) that can either accept or donate in a chemical reaction—normality is a useful measure in acid-base chemistry, redox reactions, and precipitation reactions.

Specifically, the gram equivalent weight of a solute is the mass of that substance that can react with or supply one mole of hydrogen ions (H⁺) in an acid-base reaction or one mole of electrons in a redox reaction. Thus, measuring normality in terms of gram equivalent weight per liter captures the reactivity of the solute in the context of its chemical behavior, making this measure especially relevant in quantitative analysis.

This understanding allows for precise stoichiometric calculations in solutions where reactivity varies based on the species involved, distinguishing normality from other concentration measures like molarity, which solely focuses on moles of solute without accounting for equivalence.