A weak base is a base that does not completely dissociate (ionize) in water. Instead, it reacts only partially with water to produce hydroxide ions (OH⁻).
- This means that in solution, only a small fraction of the base molecules form ions, while most remain in their original molecular form.
- Because of this, weak bases produce a lower concentration of OH⁻ ions compared to strong bases of the same concentration.
- Their solutions have a moderately high pH, but not as high as strong bases.
- Weak bases establish an equilibrium between the base molecules and the ions they form.
Examples of weak bases:
- Ammonia (NH₃)
- Methylamine (CH₃NH₂)
- Pyridine (C₅H₅N)
- Aluminum hydroxide (Al(OH)₃)
In short: A weak base is one that partially ionizes in water, producing fewer hydroxide ions and making the solution less alkaline compared to a strong base of equal concentration.