Final answer:
The acid in the reaction is HSO₄⁻, the base is HCO₃⁻, the conjugate base is SO₄²⁻, and the conjugate acid is H₂CO₃. Equilibrium lies predominantly to the right, favoring the formation of the weaker conjugate pair H₂CO₃ and SO₄²⁻.
Step-by-step explanation:
In the reaction HSO₄⁻(aq) + HCO₃⁻(aq) ↔ SO₄²⁻(aq) + H₂CO₃(aq), the species HSO₄⁻ is acting as the acid because it donates a proton (H+) to HCO₃⁻, which is the base in this reaction as it accepts the proton. As a result, the conjugate base of HSO₄⁻ is SO₄²⁻, and the conjugate acid of HCO₃⁻ is H₂CO₃.
Considering the relative strengths of the acids and bases involved, we know that H₂SO₄ (parent acid of HSO₄⁻) is a strong acid, and therefore its conjugate base HSO₄⁻, should be a weak base. Similarly, carbonic acid (H₂CO₃) is a weaker acid compared to H₂SO₄, and HCO₃⁻ is a stronger base than SO₄²⁻. This implies that the equilibrium should lie predominantly to the right, favoring the formation of the weaker acid H₂CO₃ and the weaker base SO₄²⁻. Thus, the reaction tends to produce more of the conjugate pair of the weaker acid and base.