This is a simple in class exercise to review acid- base equilibria and to lead the students to thinking about metals as both Lewis and Bronsted- Lowry acids. I use it as a discussion starter when I introduce the role of metals in biological acid/base chemistry in my upper division inorganic course, but it can be used at any level once acid-base equilibria has been covered.

This in-class activity was used on the first day of Advanced Inorganic Chemistry in lieu of lecture to review symmetry operations and point groups in small molecules.  The learning object was adapted to a small group discussion format from a fundamental quiz posted by Barbara Reisner (James Madison University) and a problem set question posted by Adam Johnson (Harvey Mudd College).