What is the relationship between Kw, Ka, and Kb?

The correct understanding of the relationship between Kw, Ka, and Kb is that Kw, the ion product of water, is equal to the product of the acid dissociation constant (Ka) and the base dissociation constant (Kb) for a conjugate acid-base pair at a given temperature. When an acid donates a proton (H+), it forms its conjugate base, while the conjugate base, when accepting a proton, can regenerate the acid. This interplay results in the relationship expressed as Kw = Ka * Kb, where Kw is specifically [H+][OH−] at equilibrium in water.

This conceptual framework highlights that at 25 degrees Celsius, Kw is approximately 1.0 x 10^-14, which reflects the equilibrium concentrations of hydrogen ions and hydroxide ions in pure water. It illustrates how acidity (represented by Ka) and basicity (represented by Kb) of a system are interconnected through the dissociation of water.

Understanding this relationship is crucial in acid-base chemistry and helps in calculations involving pH and pOH in various solutions.