Some common examples of acid-base indicators include blue grapes, which can change color from deep red in an acid to violet in a base; beets, which change from red to purplish when in a very basic substance; and blueberries, which turn red in strong acids. While these are common examples, many other things can be used as an acid-base indicator.Know More
Theoretically, if a substance undergoes a chemical change that is reversible when the pH changes, it can be used as a pH indicator. In actual use, however, the indicator must undergo a significant change in a property of the substance that is easily detectable. In most cases, the color of the object is the property that changes. Other objects, however, may have other properties, such as odor, that can change.
Many acid-base indicators are derived from plants. Flowers, fruits and other plant parts that are red, purple or blue contain anthocyanins, chemical compounds that change color if the pH changes.
Baking soda can also be used in a manner similar to an acid-base indicator. It fizzles when it is added to an acid but does not react to a base. The reaction cannot be easily reversed, however. This means that baking soda is more useful as a test to see if acids are present rather than being a true acid-base indicator.Learn more in Acids & Bases
Caffeine is a base. It occurs naturally in the leaves, fruits or seeds of over 60 plants worldwide, including coffee beans, cacao beans, kola nuts and many tea plants. In its purified form, it is a bitter white powder with the chemical formula C8H10N4O2.Full Answer >
Mixing a base with an acid results in a chemical reaction called neutralization. The result is a perfectly balanced solution of salt and water with a pH of 7 if the acid and base are balanced properly. Depending on the bases and acids used, it can be a dangerous experiment.Full Answer >
CuO, or copper oxide, is a base because it can react with acids and neutralize them. The reaction and neutralization of the acid results in a salt and water. Bases are generally metal oxides or metal hydroxides due to their ability to react with acid.Full Answer >
Red cabbage juice is a good indicator of pH because it contains flavin, a pigment molecule that changes colors according to the concentration of hydrogen ions in a solution. The juice is prepared by soaking chopped red cabbage in boiling water for at least 10 minutes and then filtering the solution to eliminate any plant material.Full Answer >