Weak base

In chemistry, a weak base is a chemical base that does not ionize fully in an aqueous solution. As Brønsted–Lowry bases are proton acceptors, a weak base may also be defined as a chemical base in which protonation is incomplete. This results in a relatively low pH compared to strong bases. Bases range from a pH of greater than 7 (7 is neutral, like pure water) to 14 (though some bases are greater than 14). pH has the formula:

Since bases are proton acceptors, the base receives a hydrogen ion from water, H₂O, and the remaining H⁺concentration in the solution determines pH. Weak bases will have a higher H⁺ concentration because they are less completely protonated than stronger bases and, therefore, more hydrogen ions remain in the solution. If you plug in a higher H⁺ concentration into the formula, a low pH results. However, pH of bases is usually calculated using the OH⁻ concentration to find the pOH first. This is done because the H⁺ concentration is not a part of the reaction, while the OH⁻ concentration is.

By multiplying a conjugate acid (such as NH₄⁺) and a conjugate base (such as NH₃) the following is given:

Since ${\displaystyle {K_{w}}=[H_{3}O^{+}][OH^{-}]}$ then, ${\displaystyle K_{a}\times K_{b}=K_{w}}$

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