1) Chemical reaction: HI(aq) → H⁺(aq) + I⁻(aq). It gives an iodide anion. 2) Chemical reaction: H₂O → H⁺(aq) + OH⁻(aq). It gives a hydroxide anion. 3) Chemical reaction: NH₄⁺(aq) → H⁺(aq) + NH₃(aq). It gives ammonia. 4) Chemical reaction: HNO₃(aq) → H⁺(aq) + NO₃⁻(aq). It gives nitrate anion.