Compare the conjugate bases of these three acids. Acid 1: sulfurous acid , H2SO3 Acid 2: carbonic acid , H2CO3 Acid 3: dihydrogen phosphate , H2PO4- What is the formula for the strongest conjugate base ?

Answer :

Acid 1:  HSO₃⁻

Acid 2: HCO₃⁻

Acid 3: HPO₄⁻²

The formula of strongest conjugate base is, H₂PO₄⁻

Explanation :

According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.

The conjugate base of the following acids are:

Acid 1: sulfurous acid , H₂SO₃

The conjugate base of H₂SO₃ by donating a proton is, HSO₃⁻

Acid 2: carbonic acid , H₂CO₃

The conjugate base of H₂CO₃ by donating a proton is, HCO₃⁻

Acid 3: dihydrogen phosphate , H₂PO₄⁻

The conjugate base of H₂PO₄⁻ by donating a proton is, HPO₄⁻²

The order of acidic strength of acid is:

H₂SO₃ > H₂CO₃ > H₂PO₄⁻

The order of strength of conjugate base is:

H₂SO₃ < H₂CO₃ < H₂PO₄⁻

The formula of strongest conjugate base is, H₂PO₄⁻