Properties of Acid & Bases
If you've ever poured baking soda into a cup of vinegar, then you have seen a reaction between acids and bases (alkalines). By definition, all substances are acid, base or neutral. You can determine if something is an acid or a base by its properties. Most tests for acidity or alkaline nature are sensory tests to determine the properties.
Other People Are Reading
-
Taste
-
The word "acid" comes directly from the Latin word for sour, "acere." Acids are therefore very sour-tasting compounds. Some well-known acids that taste very sour include lemons and vinegar. Milk that goes sour turns from a base to an acid. Although the word "base" has nothing to do with the taste, all bases are bitter. Many medicines add flavor to cover their natural alkaline bitterness.
Litmus Test
-
Early scientists noticed that certain organic dyes would react to acids and bases differently. An acid would cause the dye to change color, while the base would change it back. These characteristics became a standard test for determining if a substance was an acid or not. The dyes were put on a strip of paper (the word "litmus" means "to dye in color"), which would then be dipped in or rubbed on the substance to test for acidity or alkaline nature. Acid causes blue litmus paper to turn red, while a base substance will cause red litmus paper to turn blue.
-
Interaction
-
A very popular science experiment is to create a volcano using chemically reactive substances such as baking soda and vinegar. This experiment works because acids and bases react with one another. Baking soda is a base substance, while vinegar is an acid. You can pour two acids such as lemon juice and vinegar together and not get a similar reaction. In the same way, baking soda can be added to salt without reaction.
Electrical Conductivity
-
If you've ever made a clock using either a potato or a lemon, you have already seen that acids and bases both have electrical conducting properties. Acids and bases are often used in batteries to generate electricity. These batteries are often labeled as to whether they contain alkaline or acid materials.
Reactions to Other Substances
-
Acids react to an active metal. While metals such as platinum or gold have no reaction to acids, metals such as alkali metals, alkaline earth metals, zinc or aluminum corrode in the presence of acid. Bases also give off a reaction with the oils in your hands. When you handle a base, it dissolves the fatty acids present in your hands, turning the oils into a soapy substance and making the base feel slippery to the touch.
pH Level
-
pH stands for "potential of hydrogen," which varies depending on the acid or alkaline content of a substance. A neutral substance has a pH measurement of 7. Acidic substances measure less than 7 on the pH scale, while base substances measure greater than 7.
-
Resources
- Photo Credit photo by Alvimann
