Question

Question text In the reaction, H2PO4- + HAsO42- ⇌ HPO42- + H2AsO4-, which one of the sets below consti­tutes a conjugate (acid-base) pair?

Answer 1

Answer:

Acids give away H^+. Bases add them. Look for the one that give them away and accepts them.

H2PO4^- on the left and HPO4^2- on the right must be one pair. H2PO4^-has given one H away to something.

HAsO4^2- and H2AsO4^- must be the other pair.

So H2PO4^- has given a H to HAsO4^2-. In the process, H2PO4^- becomes HPO4^2- and HAsO4^2- becomes H2AsO4^-. It isn't that complicated. Just follow the H. It's easy to see which is missing and which has been added.

Explanation:

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