Weak base
|
|
| Acids and Bases: |
|---|
| Acid-base reaction theories |
| pH |
| Self-ionization of water |
| Buffer solutions |
| Systematic naming |
| Redox reactions |
| Electrochemistry |
| Strong acids |
| Weak acids |
| Strong bases |
| Weak bases |
In chemistry, a weak base is a chemical base that does not ionize fully in an aqueous solution. This results in a relatively low pH level. Weak bases exist in equillibrium much in the same way as weak acids do, with a Base Ionization Constant (Kb) indicating the strength of the base. For example, when ammonia is put in water, the following equillibrium sets up:
NH3 + H2O ↔ NH4+ + OH- Kb = [OH-][NH4+]/[NH3]
Bases that have a large Kb will ionize more completely and are thus stronger bases. The pH of the solution depends on the OH- concentration, which is related to H+ concentration by the Ionic Constant of water (Kw = 1.0x10-14) (See article Self-ionization of water
Examples
- Pyridine, C5H5N
- Magnesium Hydroxide, Mg(OH)2
- Ammonia, NH3