Answer to Question #164399 in Chemistry for Phyroe

Question

The use of normality as a method for expressing concentration is limited largely to acids and bases. Why is the use of normality unsuited to the expression of concentration for solution of salt?

Answer 1

Normality reflects the concentration equal to the gram equivalent weight per liter of solution. Gram equivalent weight indicates the reactive capacity of a molecule. For acid reactions, a 1 M HCl solution will have a normality (N) of 1 N because 1 mole of H⁺ ions is present per liter of solution.

Normality cannot be used for salts because its value depends on an equivalence factor that can change depending on the type of chemical reaction. For example, a solution of magnesium chloride (MgCl₂) gives 1 N for the Mg²⁺ ion and 2 N for the Cl^- ion.