Chemistry: The Molecular Nature of Matter and Change 7th Edition

Published by McGraw-Hill Education
ISBN 10: 007351117X
ISBN 13: 978-0-07351-117-7

Chapter 18 - Problems: 18.63

Answer

See explanation below.

Work Step by Step

Polyprotic acids are acids with more than one ionizable proton. For example: phosphoric acid (H3PO4) has 3 ionizable protons, therefore it has 3 Ka values. The reason successive acid dissociation constants decrease in magnitude is because it is more difficult for an H+ ion to leave a singly charged anion (like H2PO4-) than to leave a neutral molecule (like H3PO4); it's even more difficult to the proton to be "ripped off" from a doubly charged anion (like HPO42-). All polyprotic molecules follow this pattern: Ka1>Ka2>>Ka3. The smaller the Ka value is, the easier the proton will be removed.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.