Pick an acid and a base, then hand one proton across. Both conjugate pairs light up, and the real Ka values tell you which side of the balance wins.
Choose a pair below. The gold dot is the proton that moves.
A big K means the proton really does move. A tiny K means it mostly stays home.
| Acid | CH₃COOH |
| Its conjugate base | CH₃COO− |
| Base | H₂O |
| Its conjugate acid | H₃O⁺ |
| Kb of the conjugate base | 5.6e-10 |
Every pair differs by one hydrogen and one unit of charge. Take H away and the charge drops by one.
Which particle is the conjugate base of HF?