Kw (Water Dissociation Constant)

Definition

The water dissociation constant, Kw, is the equilibrium constant for the self-ionization of water into hydrogen ions and hydroxide ions. It's a measure of the concentration of these ions in pure water at a specific temperature.

Analogy

Think of Kw like a seesaw on a playground. When everything is balanced, you have equal weights (ions) on both sides. But if one side gets heavier (more ions), the other side must also get heavier to keep things balanced. This balance is what Kw measures.

Related terms

Autoprotolysis: The process by which water ionizes itself into hydrogen and hydroxide ions.

Equilibrium Constant (K): A number that expresses the relationship between the amounts of products and reactants present at equilibrium in a chemical reaction.

pH Scale: A logarithmic scale used to specify the acidity or basicity/alkalinity of an aqueous solution.