Final answer:
The balanced chemical equation for the proton transfer reaction between hydrogen phosphate ion (HPO₄²⁻) and ammonia (NH₃) is HPO₄²⁻(aq) + NH₃(aq) → PO₄³⁻(aq) + NH₄⁺(aq).
Step-by-step explanation:
To write a balanced equation for the proton transfer reaction between hydrogen phosphate ion (HPO₄²⁻) and ammonia (NH₃), we must identify the acid and base and their corresponding conjugate pairs. The hydrogen phosphate ion can donate a proton, thus acting as an acid, and its conjugate base is phosphate ion (PO₄³⁻). Ammonia can accept a proton, functioning as a base, and its conjugate acid is the ammonium ion (NH₄⁺). The balanced chemical equation for the proton transfer is:
HPO₄²⁻(aq) + NH₃(aq) → PO₄³⁻(aq) + NH₄⁺(aq)