Write a chemical equation for nh4+(aq) showing how it is an acid or a base according to the arrhenius definition.

An Arrhenius acid by definition dissociates in water to form H3O+ (or H+) ions while an arrhenius base dissociates in water to form OH- ions.

NH4+(aq) can be categorised as an arrhenius acid since it releases H3O+ ions in aqueous media

NH4+(aq) + H2O (aq) ↔ NH3 (aq) + H3O+(aq)

NH₄⁺ will act as acid according to the arrhenius definition.

NH₄⁺ will not act as a base according to the arrhenius definition.

Explanation:

According to the Arrhenius Acid-Base Theory, acids are those substances that dissolved in water divide by generating H⁺ together with an anion (ion with a negative charge). In an aqueous solution, the H⁺ protons react immediately with the water molecules to form H₃O⁺ hydronium ions. A base, on the contrary, according to this theory, is a substance that releases OH- ions in aqueous solution.

This theory is valid only in aqueous medium. And it does not consider non-protic acids (without the presence of H⁺), which are unable to release hydrogen ions, or dehydroxylated bases (they are OH- ions in their structure), unable to release OH- hydroxyl ions.

NH₄⁺ will act as acid because it has an H⁺ proton that can be released into the aqueous solution by:

NH₄⁺(aq) + H₂O (aq) ↔ NH₃ (aq) + H₃O⁺(aq)

NH₄⁺ will not act as a base because it does not have hydroxide ions that can be released into the aqueous medium.