What is a conjugate acid-base pair for the following equilibrium? H₂O(l)+ HPO₄^2-(aq) H₂PO₄^-(aq)+ OH^-(aq) A)H₂O is an acid and HPO₄^2- is its conjugate base. B)HPO₄^2- is an acid and OH^- is its conjugate base. C)H₂O is an acid and OH^- is its conjugate base. D)HPO₄^2- is an acid and H₂PO₄^- is its conjugate base. E)HPO₄^2- is an acid and H₂O is its conjugate base.

Question

Quizplus · Accepted Answer

In the given equilibrium equation, H₂O donates a proton to form its conjugate base OH^-, which can accept a proton back to reform the acid. Thus, H₂O/OH^- is a conjugate acid-base pair. HPO₄^2-, on the other hand, accepts a proton to form its conjugate base H₂PO₄^-, which can then donate a proton back to reform the acid. Thus, HPO₄^2-/H₂PO₄^- is another conjugate acid-base pair. However, this option is not given in the choices. Therefore, the correct choice is C, where the answer is H₂O/OH^-.

What Is a Conjugate Acid-Base Pair for the Following Equilibrium