What is the conjugate acid of the hydrogen phosphate ion, HPO₄²⁻?
Answer and explanation
Correct answer: D. H₂PO₄⁻
- Step 1: By Brønsted-Lowry acid-base theory, a conjugate acid is formed when a base accepts a proton (H⁺).
- Step 2: Adding H⁺ to HPO₄²⁻ yields: .
Answer
H₂PO₄⁻.
Why not the others: PO₄³⁻ is the conjugate base (formed by losing H⁺); H₃PO₄ is phosphoric acid (two protons added); H⁺ is a free proton.
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