The conjugate base of a strong acid is formed when the acid donates a proton (H⁺). For sulfuric acid (H₂SO₄), when it donates one proton, it forms the hydrogen sulfate ion (HSO₄⁻).
If H₂SO₄ donates both of its protons, the conjugate base would then be the sulfate ion (SO₄²⁻).
Thus, the conjugate base of H₂SO₄ can be represented as either HSO₄⁻ (after the first proton is removed) or SO₄²⁻ (after both protons are removed).