What is the conjugate base of H2SO3 ? Express your answer as a chemical formula
The Correct Answer and Explanation is:
Correct Answer: The conjugate base of H₂SO₃ is HSO₃⁻
Explanation:
In acid-base chemistry, a conjugate base is what remains after an acid donates a proton (H⁺). The concept of conjugate acid-base pairs is central to the Brønsted–Lowry theory, where:
Acid → loses a proton (H⁺) → becomes its conjugate base
Now consider the given acid:
H₂SO₃ (sulfurous acid)
This molecule has two hydrogen atoms that are ionizable (protons that can be donated). When H₂SO₃ loses one proton (H⁺), it forms:H₂SO₃→HSO₃⁻+H⁺\text{H₂SO₃} \rightarrow \text{HSO₃⁻} + \text{H⁺}H₂SO₃→HSO₃⁻+H⁺
This resulting species HSO₃⁻ is the conjugate base of H₂SO₃, because it’s the particle that forms when H₂SO₃ acts as an acid by donating one hydrogen ion.
It is important to note that HSO₃⁻ can also act as an acid itself and lose another proton to form SO₃²⁻, which would then be its own conjugate base:HSO₃⁻→SO₃²⁻+H⁺\text{HSO₃⁻} \rightarrow \text{SO₃²⁻} + \text{H⁺}HSO₃⁻→SO₃²⁻+H⁺
However, since the question asks for the conjugate base of H₂SO₃, the answer is the species formed after it donates just one proton, which is HSO₃⁻.
In summary:
- H₂SO₃ = Acid
- HSO₃⁻ = Conjugate base (after losing one H⁺)
- SO₃²⁻ = Second-level conjugate base (after losing another H⁺)
Understanding conjugate pairs is essential in acid-base reactions, buffers, and pH calculations.
