Answer:
The correct option is: B) H₂0 and OH⁻ as a conjugate pair
Step-by-step explanation:
According to Brønsted-Lowry theory, the acids are the chemical substances that form a conjugate base by donating a proton and bases are the chemical substances that form conjugate acid by accepting a proton.
In the given chemical reaction: PO₄³⁻(aq) + H₂O(l) ⇄ HPO₄²⁻(aq) + OH⁻(aq)
According to Brønsted-Lowry theory, PO₄³⁻ and OH⁻ are bases. Whereas, H₂O and HPO₄²⁻ are acids.
Also, PO₄³⁻ and HPO₄²⁻ are the conjugate acid-base pair; and H₂O and OH⁻ are the conjugate acid-base pair.