Richard Stenger, age 11, of Carrollton, Ga., for his question:
WHAT IS ACID?
Many different kinds of acids are completely harmless and may be taken into the body. Included in this area are citric acids which are found in lemons, limes, tangerines,
grapefruit and oranges; tar aric acid which is found in grapes; malic acid which is found in apples, and acetic acid which is found in vinegar.
Acid is the broad name of a group of chemical compounds with common characteristics They can be either organic or inorganic. When they are di solved in water, acids have a sour taste.
Acids also neutralize bases and change indicators to distinctive colors. Blue litmus, for example, will turn to red when acid hits it. Litmus is a blue coloring matter obtained from certain lichens and is widely used as a laboratory indicator.
Acid is broadly defined as any chemical substance that can combine with a hydroxl ion. An acid is, in effect, a proton donor.
Hydrogen is contained in almost all acids, but not all compounds that contain hydrogen are acids. When an acid dissolves, some of the hydrogen atoms in it are freed. They become positively charged hydrogen ions. In water, the hydrogen ions combine with the atoms of the water molecules to form the solvated hydrogen ion. All the molecules of a strong acid are converted into ions in water solution.
Inorganic acids are used in producing metals, plastics, textiles, dyes and explosives. Among the strong inorganic acids are sulfuric acid, nitric acid and hydrochloric acid.
Organic acids contain carbon atoms. Acids found in some fruit are organic, and there many different types. Oxalic acid, for example, is found in rhubarb, while benzoic acid is found in cranberries.
Amino acids contain nitrogen. They are formed from the breakdown of proteins. Several of the amino acids are essential to human life.
Some acids are poisons, even though they may be made up of the harmless common elements of carbon, oxygen and hydrogen.
Fatty acids are those that can be obtained from oils and fats. These acids, such as stearic acid, have a large number of carbon atoms.
When acids react with metals, they produce salts and release hydrogen gas.
In general, inorganic acids are powerfully active, while organic acids tend to be weak.