Question

Why is ${\mathrm{NH}}_4\mathrm{OH}$ a weak base when it has more concentration of ${\mathrm{H}}^{+}$ ions than ${\mathrm{OH}}^{-}$ ions?

Answer 1

Arrhenius bases:

• In an aqueous solution, the Arrhenius base dissociates to form hydroxide ions.
• A strong Arrhenius base completely dissociates, releasing the highest amount of hydroxide ions and metal cations in solution.
• Examples: Lithium hydroxide and Sodium hydroxide.
• Since a weak base interacts with water in small amounts, it produces fewer ions in solution than a strong base.
• Examples: Ammonium hydroxide.

Ammonia is a weak base

• Ammonium hydroxide $\left({\mathrm{NH}}_4\mathrm{OH}\right)$ is a weak base because it contains more ${\mathrm{H}}^{+}$ concentration in aqueous solution than a stronger base.
• Ammonium hydroxide partially ionized in water and produce a small number of hydroxide ions.
• The reaction is as follows:

$\underset{\mathrm{Ammonium}\mathrm{hydroxide}}{{\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right)}\rightleftharpoons \underset{\mathrm{Ammonium}\mathrm{ion}}{{\mathrm{NH}}_4^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydroxide}\mathrm{ion}}{{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$