This document discusses weak acid-base equilibria according to Bronsted-Lowry theory. It defines acids and bases as proton donors and acceptors, respectively. Conjugate acid-base pairs are introduced. Strong acids and bases completely dissociate in water, while weak acids and bases only partially dissociate. The ionic product of water, Kw, relates the concentrations of H+ and OH- ions in solution. Equations are provided to calculate the pH of solutions containing weak acids or bases using their respective acid or base dissociation constants, Ka or Kb.