Mark Roth, age 11, of Parker, S.D., for his question:
WHAT IS ALCOHOL?
The group of substances known as alcohols have unusual power to dissolve organic substances. Each alcohol has one 7eculiarity in its make up; it contains one or more carbinol groups. You write this as C O H. It stands for a hydrogen atom attached to an oxygen atom which is also attached to a carbon atom. These are one, two or three hydrogen or carbon atoms.
Alcohol is the ordinary name for a substance called ethyl alcohol, grain alcohol or pure spirits. The chemical name for pure spirits is ethanol. Alcohol is also the class name for an important group of chemicals that are recognized as having a certain definite chemical make up.
Ethanol is formed as wine or hard cider by the fermentation of any sweet fruit juice.
Industrial ethyl alcohol can be made from potatoes, grains or molasses. The grain most often used is corn. The starch of the corn is turned into fermentable sugar by a preliminary treatment with malt.
About half of all the industrial alcohol manufactured today is with a synthetic chemical process. The dilute alcohol obtained is then distilled to recover industrial alcohol of 96 percent strength, which holds four percent water. Additional treatment can make it 100 percent.
Chemically pure ethanol is a colorless liquid that looks like water but has a mild odor. It can be dissolved in water in all proportions. When exactly one gallon of pure ethanol and one gallon of pure water are mixed, the result is about 3.5 percent less than two gallons. This is because there are spaces between the water molecules, and the alcohol molecules fit partially into these spaces.
When mixing water and pure ethanol, the volume for both is then reduced. We say the volumes of the water and alcohol are not additive, or added to each other, but the weights of the water and alcohol are additive.
Proof spirit, the legal term for ethanol used by the U.S. Internal Revenue Service, is 50 percent by volume of ethanol and 50 percent by volume of water.
Ethanol dissolves many organic substances, including shellac, oils and natural and synthetic resins. It is used extensively in lacquers. It is also an ingredient of tinctures and many drug preparations.
Ethanol is also used on the body as rubbing alcohol and for sterilizing surgical instruments. One of the chemicals made from ethanol is ether.