acid/base

KoolAid and similar drinks as convenient laboratory reagents: The weak acid-strong base titration of citric acid or malic acid

The major component of a non-carbonated drink such as KoolAid or a similar beverage is usually a fruit acid, either citric acid or malic acid. The titratable acid (H+) concentration of such drinks has been found to be in the range of 0.02 to 0.04 M. A weak acid-strong base titration of these drinks with 0.1 M NaOH solution is feasible as a student exercise. Phenolphthalein indicator may be employed so long as the drink is not intensely coloured. The use of such drinks as reagents is safe, convenient, and inexpensive. Experiment instructions are included. 

Expanding on Self-Inflating Balloons: Activities Involving Moles, Gas Laws, and Thermochemistry

Balloons that inflate using carbon dioxide produced from the reaction of citric acid and sodium hydrogen carbonate can be used to demonstrate a number of aspects of chemistry. Gas laws were used with the balloons to illustrate limiting reactants, molar mass of gases, and rockets. The endothermic reaction in the balloon was visualized with an infrared camera, and the Green Chemistry aspects of these balloons were considered.

Food Dyes as Acid-Base Indicators

Natural food dyes are being sold online and in stores that can be used as acid-base indicators. These dyes open up a host of possibilities for at-home and in-class. For example, these food dyes can be used as indicators in the quantitative titration of the Mg(OH)2 in milk of magnesia.

Thermal Paper as a Polarity and Acidity Detector

Thermal paper such as that used for point of sale receipts typically functions by darkening when exposed to heat. The pigment system used in this paper also darkens when exposed to solvents of intermediate polarity and acids. This enables thermal paper to be used as an inexpensive sort of indicator paper for a variety of demonstrations.