This activity is designed to give students practice with predicting the preferred direction of double displacement reactions using the hard-soft acid-base (HSAB) principle. It includes a question where students must determine the relative softness of two soft bases. This activity was used after the lecture where students were introduced to these concepts.
Students should be able to:
- Separate a compound into a Lewis acid and a Lewis base
- Assign the acid and base as hard, soft, or borderline
- Use these assignments to predict the direction that a reaction will proceed
- Identify which atom will serve as the electron pair donor in a polyatomic Lewis base
- Determine the relative softness of two soft species
I have the students work on the activity in groups and then we discuss it together at the end of class. When I used the activity I was teaching via Zoom, so I had students collaborate with their group in a Google Doc (one page per group) and I followed along while they were in their breakout rooms. I taught my class in a flipped format, so the activity is designed to take a full 50 minute class period, including introduction, group work, and full class discussion.