What is the conjugate acid of HPO4^2-(aq)?
A. H3PO4(aq) B. HPO4^2-(aq) C. H2PO4-(aq)
D. PO4^3-(aq) E. H3O+(aq)
To determine the conjugate acid of HPO4^2-, we need to understand the concept of conjugate acids and bases.
In a chemical reaction, when a base donates a proton (H+), it forms its conjugate acid. In this case, HPO4^2- can act as a base by accepting a proton, thus forming its conjugate acid.
To identify the conjugate acid, we need to add a proton (H+) to the HPO4^2- ion. When we add one proton to HPO4^2-, the resulting molecule is H2PO4^-. So the answer is C. H2PO4^-(aq).
I've never fully understood why students have trouble with conjugate acids/bases.
If you want the conjugate acid of something, add a H^+ to what you have. If you want the conjugate base of something, take a H^+ away from what you have.