Final answer:
The Kb formula for the given reaction is Kb = [H3O+][NH4+]/[NH3]. It relates the concentrations of the hydronium ion (H3O+), ammonium ion (NH4+), and ammonia (NH3).
Step-by-step explanation:
The Kb formula for the given reaction is:
Kb = [H3O+][NH₄+]/[NH₃]
This formula represents the equilibrium constant for the reaction NH₃ (aq) + H₂O(l) <--> OH - (aq) + NH₄ + (aq). It relates the concentrations of the hydronium ion (H3O+), ammonium ion (NH₄+), and ammonia (NH₃).