Final answer:
The acid ionization reaction for HNO₃ is (C) HNO₃ (aq) ↔ H+ (aq) + NO₃⁻ (aq), which shows complete ionization characteristic of a strong acid.
Step-by-step explanation:
The correct acid ionization reaction for HNO₃ (nitric acid) when it dissociates in water is represented by the equation:
HNO₃ (aq) ↔ H+ (aq) + NO₃⁻ (aq)
This reaction shows the dissociation of nitric acid into a proton (H+), also known as a hydrogen ion, and the nitrate ion (NO₃⁻) in an aqueous solution.
This process is characteristic of a strong acid, which ionizes completely in water, unlike a weak acid which only partially ionizes and sets up an equilibrium.