pKa pKb Calculator
Calculate and convert between pKa, pKb, Ka, and Kb. pKa + pKb = 14 at 25C
pKa + pKb = pKw = 14 (at 25 C)
Common Acids:
Common Bases:
pKa
4.7400
Weak Acid
pKb
9.2600
Very Weak Base
Ka
1.8197e-5
Kb
5.4954e-10
Verification:
pKa + pKb = 14.0000 (should equal 14)
Relationships:
pKa = -log(Ka)
pKb = -log(Kb)
Ka x Kb = Kw = 10^-14
pKa + pKb = pKw = 14
Understanding pKa and pKb
pKa and pKb are measures of acid and base strength, respectively. A lower pKa indicates a stronger acid, while a lower pKb indicates a stronger base. For a conjugate acid-base pair, pKa + pKb = pKw = 14 at 25C. This relationship allows conversion between acid and base constants for conjugate pairs.
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Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
Formula Source: Chemistry: The Central Science
by Brown, LeMay, Bursten