Acid Base

The disappearing rainbow¹ is a wonderful chemistry demonstration previously featured here on ChemEdX.^2-4 In this experiment, a colorless solution of NaOH is poured into a row of flasks, each containing a different acid–base indicator.

Dean Campbell*, Ali Patel, Kathryn Campbell *Bradley University, Peoria, Illinois

The purpose of this article is to show how a microtitration can introduce Honors Chemistry students to titrations.

In February 2025 we discussed using particle diagrams, calculations, and titration curves to support student understanding of acids, bases, and buffers.  

Josh Kenney, Melissa Hemling, and I just published an article in the October 2024 Journal of Chemical Education. The article describes inquiry-based activities that highlight the chemistry behind “No-Mess” picture-coloring books.¹ Well, it turns out that our timing is impeccable.

Phenolphthalein has been used extensively as a pH indicator.¹ Although the compound actually can exhibit multiple color transitions, it is best known for turning from colorless to pink in aqueous solution as the pH is raised above 8.3.¹ The equilibrium associated with this transition is shown in Figure 1.

As educators, we are always looking for ways to make complex concepts more accessible and memorable. In the early 2000s, I attended the Biennial Conference on Chemical Education (BCCE), where I learned about a brilliant brain break activity from renowned chemistry teacher Lee Marek.

Co-Authored by James W. Webb* and Otis Rothenberger* *Department of Chemistry, Illinois State University, Normal, IL 61790

Gentle Reader, our story today follows a number of storied histories, most conspicuously in the representation of transformation—making and breaking bonds—in a chemical reaction. Flowcharts, which use arrows to dynamically illustrate a process, also have a storied history, particularly in programming in Computer Science. Titrations have a stor