Weak acids and bases partially dissociate in water, establishing equilibrium. Their strength is measured by the acid dissociation constant (Ka) and the base dissociation constant (Kb). A larger Ka or Kb indicates a stronger species. The constants are linked by the vital relationship: Ka x Kb = Kw, where Kw = 1.0 x 10-14 at 25°C. This relationship connects an acid's strength to the strength of its conjugate base.