Convert between Kb and pKb and relate it to the conjugate acid.
A base is half protonated at pH equal to the pK_a of its conjugate acid. Converting pK_b to that pK_a is usually the quickest route to predicting behaviour at a given pH. Amine drugs are largely protonated at stomach pH and largely free base in blood, which is exactly this relationship in action.
pKb
pK_b = −log₁₀K_b; pK_a(conjugate) = 14 − pK_b
pK_b = −log₁₀K_b; pK_a(conjugate) = 14 − pK_b A base is half protonated at pH equal to the pK_a of its conjugate acid. Converting pK_b to that pK_a is usually the quickest route to predicting behaviour at a given pH.
Amine drugs are largely protonated at stomach pH and largely free base in blood, which is exactly this relationship in action.
This calculator takes 2 inputs: Base dissociation constant, Solution pH. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.